ROCKET TEAM: DESIGN PACKAGE

Transcription

1 Facet 1 RECOGNITION AND QUANTIFICATION OF NEED Market Demand Recruitment is the most effective way to show high school students what a specific college is about. By traveling to prospective audiences, a school can sell itself on why they should choose as their place of higher education. By getting more students to attend that university, more funding can be given to the school, and companies will invest in the school for resources to further improve students experiences. Many students are interested in hearing talks about the educational programs and the different types of majors available to them. In addition, they want to know the details of what these majors can do for them, especially in terms of acquiring jobs and careers; they want to know what kind of classes they will take and what work they will learn how to do in the future. Presentations and demonstrations are both good ways to show this; for the NMSU College of Engineering and the Mechanical and Aerospace Department, studentcreated demonstrations of projects can be shown to prospective students concerning what type of classes, research, and work they can do in college. Undergraduate research and Senior Design Capstone projects are among the best possible demonstration units to show students what mechanical and aerospace engineers do. These projects could also be used for future research and laboratory experiments as well, especially in the field of aerospace engineering. This project could be used to experimentally check researched data in many areas related to fluid dynamics, propulsions, controls, and other aerospace-related subjects. Research conducted using these projects can further the prestige of the department. By solving new and unknown problems, students will have the opportunity to write and submit research into journals, gain first hand experimental and research experience, and the understanding of how research is conducted amongst engineers. The reasons above show how important beginning-level research projects are to the students, the department, the academic world, and the recruitment of future students. By carefully determining what type of research can be used as a recruitment tool, student research projects and laboratory experiments can be used to conduct academic research and current students can be assigned to projects that fulfill their needs. New Mexico State University Spring 2012 Page 1

2 Solution Assessment Currently, southern New Mexico has become a very important location in the field of Aerospace Engineering. New Mexico State University has opened an undergraduate program in the field of Aerospace Engineering in 2006 and a graduate program for Aerospace Engineering in Spaceport America was opened in 2006, 45 miles north of New Mexico State University. The spaceport will be the eventual launch site of White Knight Two, designed and built by Virgin Galactic, which is the first privately-owned suborbital spacecraft. These developments have led to a growth of the private industry in Aerospace Engineering in the southern New Mexico area. Thus, research projects given to NMSU Engineering students should be related to the field of Aerospace Engineering in particular propulsions. Rockets have always been a fascination of the American people and scientists. With the association of the history of rocketry in New Mexico with the current growth of rocketry in New Mexico, a project that would appeal to local students and that be used academically would be a rocket-based project. Since rockets come in all sorts of shapes, sizes, configurations, and types, the possible list of projects is endless. However, to meet the needs of demonstration and research requirements, many projects would not qualify for the stated needs. The following deductions can be made from the needs stated above. The project needs to be portable. The project needs to be set up easily for engineers. The project needs to have interchangeable parts. The project can be set to a fully-automated control. The project needs to be set up with the ability of accurately acquiring data. From NASA and NMSU engineers, the idea to make a joint project that can fulfill the requirements above was born. The idea permeated into a rocket-based project that can be used by NASA and NMSU for recruitment, laboratory testing, and experimental design processes. NASA has interest in this for its educational outreach programs, and evaluating students at the collegiate level by using the project for research and experimentation. The NASA Mission Directorate that supports this research is the Exploration s, which encourages a diverse range of students to become involved in the science and technology areas relevant to NASA. After collaboration from NMSU, NASA, and speaking with Dr. Ed Conley of the NMSU MAE department, the hybrid rocket project was born. The idea of this project is to create a compelling hands-on facility, which will give an Aerospace Engineering (design/build/test) experience. This is to be coupled with immersion in the instrumentation and information management systems that will prevail in the new century. Specifically, this small, portable Hybrid Rocket Test Stand instrumented will offer what s known as discovery-learning designed to maximize the ever more limited time and resources that engineering students can devote to the real world. New Mexico State University Spring 2012 Page 2

3 Along with this project idea came requirements and guidelines set by NASA in order to create a device worthy of safely having the ability to enlighten and capture the eye of prospective students. These requirements are listed below from 1 to CPD shall be easily portable. Able to move from a car/truck to a classroom via one person. Envision a suitcase size device. 2. CPD Combustion products shall not be toxic, nasally overbearing, or visually disturbing (i.e. not much smoke, don t want to set alarms off) 3. CPD shall be able to be set up in no more than 15 minutes. 4. CPD shall have the following instrumentation: Thrust Measurement, Oxidizer flow, Chamber Pressure, Gas Oxygen Temperature, Nozzle Exit Temperature, Battery voltage. 5. CPD shall be able to perform a preset thrust profile (i.e. Oxidizer flow automatically adjustable). 6. All CPD components shall be able to be repaired or replaced in the field. 7. All CPD instrumentation shall be able to be replaced with spare in the field. 8. All CPD instrumentation data will be displayed on a flat LCD screen. 9. CPD data from firings shall be saved and easily retrieved. 10. Activation and Control of CPD shall be automatically with provision for manual control. 11. The CPD shall have a reusable in place ignition system. 12. CPD shall be able to fire continuously for duration greater than 20 seconds. 13. CPD shall be able to do at minimum 4 test firings in one hour. 14. The CPD controls shall assess readiness for operation (eg. Electrical power; Igniter continuity; oxidizer pressure; article temp for restart). 15. CPD demonstrator shall be able to present a pre-recorded data of actual rocket testing on its LCD screen. 16. CPD shall operate via graphic user interface. 17. CPD shall display propulsion graphically. Showing discharge changing in respect to fuel and oxidizer changes. 18. CPD shall graphically show the relationship between all propulsion variables. 19. Both recorded data and video shall be time-stamped. 20. The post-test data shall be time-aligned to a start event. 21. CPD shall have an Emergency Shut-Off capability which will remove the oxygen supply from the device. 22. Data Display shall not interfere with data acquisition and recording operations. 23. CPD shall be capable of firing horizontally. 24. CPD design team shall provide end-to-end system uncertainty calculations in terms of percentage of full scale ranges. New Mexico State University Spring 2012 Page 3

4 Budgetary Parameters ROCKET TEAM: DESIGN PACKAGE The budget for the hybrid rocket project was provided by NASA and the NMSU MAE department. The initial budget for the current semester is about $1,500. Before this project was given to the Capstone team, many areas of the project were already worked on by individual students with the guidance of Dr. Conley. The following list best describes the budget parameters set forth for this project: Pipe Adapters Allen Screws Load Cell Flow Meter New Mexico State University Spring 2012 Page 4

5 Facet 2 PROBLEM DEFINITION Design Objective The overall objective of this project is to develop a hybrid rocket and test stand instrumented with any number and types of modern sensors. The design of this hybrid rocket and test stand is to be small and portable (suitcase size); the basic apparatus will be used for demonstrations in rocket propulsion. The design will also include all of the needed hardware to operate the hybrid rocket unit (with the exception of the external oxygen tank, regulator, fire extinguisher, and table). It is to be equipped with chamber pressure, a flow meter to measure the amount of oxygen flow, and thrust sensors at a minimum, making it compatible with a laptop analog card. The design of this project will also include making the correlation between the rocket s thrust and its size, the appropriate transducers (physical size, resolution, range, and cost), the ease of setup, and its portability. The data acquisition and analysis software includes LabVIEW and for any general physical modeling, Unigraphics software will be used. The design objective was formed by NASA and Dr. Conley to fit the required needs of the project. Since the project was reduced to a specific hybrid rocket setup, the needs could be even further refined. Design Constraints Restrictions will apply in the design of the portable hybrid rocket unit. They will be defined into the following categories: Budget Funding was provided by NASA, but has been used up by previous researchers working with Dr. Conley. The money was used to purchase needed hardware and testing equipment for the DAQ systems of the hybrid rocket. Time Time proved to be a constraint for the overall objective of this project. Previous students have contributed research to this project since spring 2010, and were only able to research instruments for DAQ use, materials for the rocket design, and create the engine for the rocket, which was redesigned in the fall 2011 semester. Since this has been an ongoing project, each semester has been given a set goal to accomplish. The spring 2011 Capstone team s main goal was to finish creating the rocket engine. This included finding the right type of fuel, finding the right material to make it out of, creating it a compact size, and making an ignition system. The fall 2011 Capstone team was given the task to better the equipment used. A few examples include making the rocket lighter, compacting the Data Acquisition, and enlarging the test stand to the length of the rocket to eliminate more error in the data. To accomplish these goals the Capstone Design Team was split up into sub-groups. Each of these sub-groups has allotted a great amount of time to each section of the project. Most of the time has been focused on the electrical portion of New Mexico State University Spring 2012 Page 5

6 this project. The spring of 2012 Capstone team focused on the design of a reusable ignition system, improving upon previous designs, completing the electrical circuits, and insuring the rocket is complete and ready to be delivered. Like previous semesters the team split into sub-groups to focus on ignitions, electrical design, and case construction. Legality and Safety The legality of this project is closely associated with the safety aspects of the rocket, and thus the constraints from these two are associated. When this project is being used as either a demonstration device or an experimental device, the safety of the operators must be ensured. This also pertains to those who are observing the procedure while the hybrid rocket unit is being used. One requirement that constrains operators using this device is reading and understanding the safety guide and manual for the hybrid rocket unit. The manual has been typed up by the researchers working on this project will accompany the rocket to all of its locations. Any operator who plans to use the rocket for any purpose must first read the manual and follow the procedure given on how to run a test or demonstration. The manual includes the correct assembly procedure of the unit for each use (experimental setup and demonstration setup). It ensures assembly components are checked and rechecked to ensure they are connected correctly. It appropriates operating area definitions for each type of setup, and defines limitations on test length, mass flow control rate, and thrust. Proper attire, including safety equipment, will be detailed in the manual, as will correct testing and disassembly procedures. Operators who do not read the manual will endanger themselves, co-workers, and spectators of the hybrid rocket unit, and can be held liable for legal damages. Personnel Personnel constraints will break down into the following categories: Knowledge Team members of the hybrid rocket unit project had to expand their knowledge base in the areas of hybrid rockets, LabVIEW and DAQ systems, and refresh the knowledge base in areas of statics, thermodynamics, and fluid dynamics. Safety The safety of the hybrid rocket project is referenced in the Safety Manual. The Safety Manual is located in the Detailed Design section of the document. Teamwork The ability for the team to adhere to a team contract, which includes regularly attending meetings, voicing opinions and contributing ideas to the group, completing assigned tasks, and informing the group in a timely manner of the details of the assigned work. New Mexico State University Spring 2012 Page 6

7 Material Properties and Availability Material property and availability also go hand in hand with the team s budget. Most of the material needed for this semester had been previously bought and include the fuel grain, Teflon, flow meter and the DAQ instrument devices. Other materials such as the aluminum have been supplied by NMSU. The materials that presented any issues during this semester include the pipe adapters and the flow meter. The pipe adapters proved to be hard to find because of the different types of threads on the chosen adapters. These types of fittings are special ordered and are not found in stores. The flow meter can only be ordered online and was shipped from the National Instruments Company. The flow took a few months to program. Manufacturability The NMSU Student Project Workshop is open for approximately 9-10 hours a day, five days a week. Thus, the accessibility to manufacture parts is relatively easy. The parts needed to be manufactured include the rocket top and bottom plates which are made out of aluminum. In order to test a reusable mechanical ignition another aluminum top plate was built with an experimental diffuser plate. Graphite nozzles were also produced to experiment with different flow rates. Since, the machine shop does not have specific carbon-cutting tools, a graduate student allowed the nozzles to be created at his own shop. Listed in the Design Specifications section is a description of each. New Mexico State University Spring 2012 Page 7

8 Design Specifications The requirements of the design were defined by NASA and Dr. Conley, which are stated above. Previous researchers associated with Dr. Conley have derived design specifications to direct the project in a specific direction to meet the project needs. The specifications they have made were in the areas of DAQ instruments, the hybrid rocket fuel grain and motor assembly, use of oxygen as liquid fuel, the frictionless slider, and ignition system. The following outline defines the specifications that the Capstone Hybrid Rocket team have followed in order to meet the goals: Portability Size of carrying case is approximately the size of a typical to large suitcase. The case needs to carry the hybrid rocket motor, testing instruments, and hardware assembly. Test Instruments The areas to be experimentally analyzed are the thrust, oxygen flow, and the back pressure of the rocket unit. The thrust is calculated by using a system that utilizes load cells, the oxygen flow is measured using a power supply, the back pressure is measured using a pressure transducer, and all the testing devices use a DAQ National Instruments system. The LabVIEW program is used to visually show live data and record it to be used in analytical calculations and analysis of the rocket. Hardware Hardware was machined as necessary from scrap parts or purchased parts. The hardware was used to secure either the rocket itself, the testing instruments, or the plumbing into place. Plumbing A plumbing system was used to transport oxygen from its tank to the rocket. The parts of the plumbing system are oxygen cleaned and air tight. The plumbing system also incorporates a mass-flow control unit, as well as a solenoid and needle valve for safety purposes. New Mexico State University Spring 2012 Page 8

9 Facet 3 CONCEPT DEVELOPMENT Brainstorming Techniques From the desired project needs and specifications, previous researchers with Dr. Conley brainstormed concepts that would meet the needs of the hybrid rocket project. The concepts associated with the hybrid rocket will be broken down into four categories: nozzle, hardware, plumbing, and DAQ systems. Each of these areas has a specific input into the project, and will be broken down into separate engineering tasks. Each of the areas of concept design will have their own needs and specifications derived or allocated from the needs and specifications of the overall project. The team/engineers working within each individual concept will first plan out their systems in general for review, verification, and validation. The concept designs will have the following needs and requirements. Ignition The purpose of the ignition system is to develop an ignition that will run multiple times without having to replace it. This is a requirement that NASA has designed to be able to show multiple tests without having to change out any piece of the rocket system. This reusable ignition needs to be safe and easy to use and withstand the temperature and pressure of the oxygen and flame. The designs of each ignition system will be described in the Preliminary Design Section. Plumbing The purpose of the plumbing concept development is to meet the needs of providing the liquid fuel from its tank to the hybrid rocket in a safe and controlled way. As mentioned above, the liquid fuel for this project will be oxygen. Devices that will be needed for this system will include a pressure regulator, solenoid valve, hoses, adapters, a needle valve, pipe connectors, Teflon tape, swivel adapters, and a mass-flow control unit. The nature of these parts will be to work with oxygen, so the preference is to have them suited for oxygen use or to have them oxygen-cleaned. This means that the parts will have to be purchased instead of manufactured. The design of the flow system needs to have checks to control the flow for safety purpose. This will be accounted for by having the liquid fuel flow from the tank first enter through the solenoid valve, to the mass-flow control unit and from there to the needle valve. This theory will restrict the order of the parts of the plumbing system. The specifics of the plumbing system will be discussed further in the Preliminary Design Section. New Mexico State University Spring 2012 Page 9

10 Nozzle Since the nozzle is able to change the thrust depending on how it is made, the nozzle will need to be made up to certain standards set by Dr. Conley. These standards that Dr. Conley has set are given in a binder. From these standards the nozzle is required to produce a shock diamond that can be seen at the end of the nozzle and hit a desired Mach 2 or March 3. Data Acquisition s The Data Acquisition (DAQ) Concept Design system will need to govern what data will be recorded, how it will be recorded, and for how long/how often. Described from the needs above, the thrust, oxygen flow, and back pressure are to be measured from the hybrid rocket system during use to determine scientific characteristics that can be used to describe the rocket. The specific instruments that will be used to acquire the data for each system are as follows: a load cell for thrust, power connection to the flow meter, and a pressure transducer for back pressure. As needed, hardware or plumbing will be manufactured or purchased to be able to correctly acquire the data as efficiently as possible. A combination between the hardware concept design and the DAQ concept design will create the setup in which the load cell can be properly arranged to acquire the data. As well as a combination between the plumbing and DAQ concept design will create a setup for the pressure transducer. The flow meter will also be connected to the DAQ along with a power supply. Each of the testing instruments will be connected to one DAQ module, this will allow for both an input and output signal to each device. This DAQ module is a National Instrument box which will allow for a simple connection and is more compact. LabView The LabView program will need to be easily to use and operate the entire system. The program will start the flow of oxygen and control the flow rate, once it reaches the desired flow rate then the ignition will be lit using a second LabView program that only ignites the fuse. The thrust, oxygen flow and back pressure need to be recorded through the use of the first program. The LabVIEW program records data at 2000 Hz, shows the output signals graphically and through visual dials, it exports data to a text file, and ignites the ignition system that starts the rocket motor. New Mexico State University Spring 2012 Page 10

11 Facet 4 FEASIBILITY ASSESMENT As this is a continuing project, all items assessed include redesigns and refabrications, along with possible re-direction ideas. Below is a list and description of six (6) items, followed by an analysis consisting of eight (8) guiding questions, derived from four (4) categories: technical, economic, scheduling, and marketing. The questions examine the impact of each item s implementation by assigning it a score of 1 (least beneficial), 2 (fairly beneficial), or 3 (most beneficial). The scoring system applied to these impacts will assist in ranking the importance of the new items and ideas, allowing the quantification of the value of each. Item/Idea Descriptions Item 1: Chemical Ignition The current rocket engine utilizes a non-reusable pyrotechnic ignition system. A reusable ignition system is required by NASA. A chemical ignition system is proposed using a lighter to inject and ignite butane fuel in the system in order to ignite the solid rocket fuel. Item 2: Electrical Ignition An electrical ignition system is proposed utilizing a resistance wire and high current power supply to heat the fuel grain to the point of combustion. Item 3: Mechanical Ignition A mechanical ignition system is proposed using hand-held butane lighter components to produce a shower of burning particles or sparks to be carried through the top plate into the fuel grain to ignite the engine. New Mexico State University Spring 2012 Page 11

12 Item 4: Redesign and Re-fabrication of the Nozzle Currently the nozzle installed in the rocket engine is not manufactured to allow for maximum efficiency of the engine. A complete redesign and re-fabrication of multiple nozzles is required to achieve the best efficiency of the engine at set operational parameters. Item 5: Electronics and Controls To date; the operation and control of this system is manually completed. The system is ultimately required to operate nearly autonomously with minimum human interaction along. The redesign and re-fabrication of control electronics is sought to achieve this requirement along with portability requirements set forth by NASA. Item 6: Suitcase Portability At present, the entire system is placed on a test bed that is not readily transportable. The system is ultimately required to be portable and easily deployable within a time limit of 15 minutes by NASA. A conveniently transportable suitcase outfitted with shock control measures is proposed to achieve this requirement. New Mexico State University Spring 2012 Page 12

13 Item Analysis Question Category: Technical Question 1: Is this item capable of producing a noticeable increase in performance? Scoring : 1: Least Beneficial - not capable of producing any increase in performance 2: Fairly Beneficial - capable of producing a moderate increase in performance 3: Most Beneficial - capable of producing a significant increase in performance 1 Point 2 Points 3 Points Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Refabrication of the Nozzle Electronics and Controls Suitcase Portability New Mexico State University Spring 2012 Page 13

14 Question Category: Economic ROCKET TEAM: DESIGN PACKAGE Question 2: Does this item require less material? Scoring : 1: Least Beneficial - requires an excessive amount of materials 2: Fairly Beneficial - requires more material than alternatives 3: Most Beneficial - requires a reasonable amount of materials 1 Point 2 Points 3 Points Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Refabrication of the Nozzle Electronics and Controls Suitcase Portability New Mexico State University Spring 2012 Page 14

15 Question Category: Economic ROCKET TEAM: DESIGN PACKAGE Question 3: Is it necessary to use special equipment for this Item? Scoring : 1: Least Beneficial - requires expensive specialty equipment 2: Fairly Beneficial - requires the use of some tools that may be outsourced for a reasonable price 3: Most Beneficial - requires the use of standard hand tools or no tools at all 1 Point 2 Points 3 Points Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Refabrication of the Nozzle Electronics and Controls Suitcase Portability New Mexico State University Spring 2012 Page 15

16 Question Category: Economic ROCKET TEAM: DESIGN PACKAGE Question 4: Are the required materials expensive? Scoring : 1: Least Beneficial - requires materials that are out of the clients budget range 2: Fairly Beneficial - requires materials that are just within the clients budget range 3: Most Beneficial - requires materials that are well within the clients budget range 1 Point 2 Points 3 Points Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Refabrication of the Nozzle Electronics and Controls Suitcase Portability New Mexico State University Spring 2012 Page 16

17 Question Category: Scheduling ROCKET TEAM: DESIGN PACKAGE Question 5: Is there enough time to complete this item? Scoring : 1: Least Beneficial - requires more time than is allotted 2: Fairly Beneficial - requires more time than allotted solely to complete testing 3: Most Beneficial - will be completed within the allotted time and have ample time for testing 1 Point 2 Points 3 Points Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Refabrication of the Nozzle Electronics and Controls Suitcase Portability New Mexico State University Spring 2012 Page 17

18 Question Category: Scheduling ROCKET TEAM: DESIGN PACKAGE Question 6: Will this item require outside help to complete? Scoring : 1: Least Beneficial - requires an excessive amount of outsourcing 2: Fairly Beneficial - requires some outsourcing 3: Most Beneficial - requires minimal to no consultation to complete 1 Point 2 Points 3 Points Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Refabrication of the Nozzle Electronics and Controls Suitcase Portability New Mexico State University Spring 2012 Page 18

19 Question Category: Marketing ROCKET TEAM: DESIGN PACKAGE Question 7: Is this system marketable with the new item? Scoring : 1: Least Beneficial - amount of marketability gained does not warrant the change 2: Fairly Beneficial - amount of marketability gained is somewhat attractive 3: Most Beneficial - amount of marketability gained is very attractive and offers a swift ROI (return of investment). 1 Point 2 Points 3 Points Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Refabrication of the Nozzle Electronics and Controls Suitcase Portability New Mexico State University Spring 2012 Page 19

20 Question Type: Marketing ROCKET TEAM: DESIGN PACKAGE Question 8: Does this system require a client with high investment resources? Scoring : 1: Least Beneficial - requires a client with substantial financial resources 2: Fairly Beneficial - requires a client with moderate financial resources 3: Most Beneficial - will be suitable for a client with little to no financial resources 1 Point 2 Points 3 Points Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Refabrication of the Nozzle Electronics and Controls Suitcase Portability New Mexico State University Spring 2012 Page 20

21 Item Impacts Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Total Chemical Ignition Electrical Ignition Mechanical Ignition Redesign and Re-fabrication of the Nozzle Electronics and Controls Suitcase Portability With the impacts above it was decided that all items were to be addressed this semester. The system was expected to be completed and delivered by the end of this term. New Mexico State University Spring 2012 Page 21

22 Facet 5 PRELIMINARY DESIGN Design 3 During the spring 2012 semester the main focus has been to design a reusable ignition system. There have been 3 different attempts and assigned different team members designing each system. We tested each of the ignition systems to determine if they would light the rocket successfully without any hazards. The ignition systems included: Ignition #1: Resistance Wire Ignition Test Ignition #2: Gas and Igniter Ignition #3: Mechanical Unfortunately, all ignition designs were undesirable. The Mechanical system worked the best and could be considered later with further testing. The current ignition system utilizes fuses that ignite when electrically charged. Each fuse is Halliburton welded into a 3/8 NPT to ¼ PE adapter in order to create an air tight seal. The fuse adapter combination could then be screwed directly into the plumbing assembly. This configuration placed the fuses right into the back of the combustion section of the rocket. The fuses could then be ignited when charged with a 12Vdc battery. This method has proven to be very reliable and incorporated only a small set up procedure. Other major work this semester was to design a portable case that would allow transporting the hybrid rocket easily along with meet requirements from NASA. We also worked on fixing calibration and improving our nozzle design. The focus of the previous semesters work was primarily on testing with mobility being further out of scope. From the results of that testing it was concluded that the first design lacked the sensitivity needed to record accurate thrust data. The second design acquired more accurate data but was crude and far from mobile. With that in mind, the goal of the third redesign was to fabricate a test stand that could be easily transportable and take meaningful data measurements. Apparatus New Mexico State University Spring 2012 Page 22

23 Last semester the rocket motor underwent two minor modifications in design 3. First the inlet base was remanufactured to be lighter and slightly smaller. Thermocouple measurements from the previous semester provided the insight needed to make this decision. The new part was manufactured from aluminum and is a quarter inch thinner than the old. Previous ignition ports that are no longer used were also left out of the new component. All other geometric entities of the part remained constant. The nozzle used in previous semester s tests was fabricated based off drawings provided from NASA in the student project center at NMSU. However the student project center lacked sufficient tools to precisely produce the specifications. Last semester an outside machine shop was utilized to improve nozzle performance. The geometry of the nozzle also changed after research was conducted in nozzle theory. The diverging section was tapered to 30 and the throat of the nozzle was tightened to an eighth of an inch. More advances in the nozzle design under way along with more testing. Design 3 incorporated a bending beam load cell for taking thrust measurements. Initially load cells used in measuring the thrust of the hybrid rocket were oversized. Therefore with the third design came the most sensitive load cell thus far. The bending beam load cell used at the beginning stages of design 3 had a working range of 5lbs. However mid semester that load cell became non-functional and required replacement. This gave an opportunity to decrease the operating range once again. This in return increased the sensitivity. The new load cell has a working range of 600 grams or approximately 1.3 lbs. This load cell was mounted directly underneath the inlet end of the rocket motor. The opposite end was held in place by pinned connection. This pinned support restricted translation in the vertical and transverse direction, but allowed for translation in the axial direction. With these constraints in place the rocket was able to produce thrust in the axial direction causing a force to be placed on the load cell. Pressure data was taken in the same fashion as design 1 and 2. In these designs the calibration for the testing instruments became key in making sure the changes in voltage of the instruments actually represent what is really changing in force, pressure, or temperature. This was done through calibration tests, with the load cell being the main device that was calibrated. New Mexico State University Spring 2012 Page 23

24 Figure 1 and 2: Left: Side view of rocket and test stand. Right: Isometric view of rocket and test stand assembly. In both views the pinned supports can be seen on the right side, underneath the nozzle end, and the load cell can be seen on the right side of the test stand under the inlet side of the motor.. Safety in the third design has also been revised. Last semester was the first design to incorporate an automatic shutdown switch. A solenoid valve was inserted into the plumbing system. When electrically charged the solenoid valve is opened and allows the oxygen to flow into the rocket motor. The switch that provides power to the solenoid valve has a latch when pressed action, therefore the automatic shutdown switch must be pressed for the entire duration of the test. Once the switch is released the solenoid valve loses charge and cuts the flow of oxygen to the rocket. Efforts were also made to integrate the ignition system with the cutoff switch. Ideally the system will fire with the initial pressing of the shutdown switch and terminate when the switch is released. The mass flow controller used in design 1 and 2 is also incorporated in the current setup. The controller function has yet to be fully integrated because of difficulties presented with programming the instrumentation. Rather the mass flow controller has been used as a gauge by providing measurements on flow rate. A second more easily programmable mass flow controller has been ordered at the beginning of the fall semester but has yet to arrive. Design 2 Drawings may be seen on the following pages in the Spring 2011 section. The overall rocket and plumbing assembly for the Spring 2012 semester can be seen in Figure 5. New Mexico State University Spring 2012 Page 24

25 The DAQ and control system are used to control the ignition switch, pressure transducer, oxygen flow, the load cell, and any other device needed and or wanted. Although, the same idea is the same as the previous semester the setup was changed and is more compact. Instead of each device having its own module inserted into a chassis unit and having a power supply, the unit for this semester still has a power supply but has only one module that connects all of the devices and connects to a computer through a USB device. Just as before the program that allows the data to be collected and that will control the system is LabVIEW. Last semester a LabVIEW Program was designed to interpret data from one load cell, one pressure transducer, and the oxygen flow rate. The LabVIEW layout below shows the input from the strain gauge, voltage form the transducer, and the oxygen flow unit running into a sample clock. The clock tracks the time data and allows the user to set the amount of data taken per time unit as desired. The timed data is then run into a loop that activates at a button push and begins to record the data. The data is then exported to a waveform file and converted in an excel spreadsheet for data interpretation and interpolation. In Figures 3 and 4 the Front Panel and Block Diagram of LabVIEW are shown from this semester. Figure 3: Front Panel New Mexico State University Spring 2012 Page 25

26 Figure 4: Block Diagram Since this is a continuation project and it is still in the process of improving everything is subject to change. For this semester procedures are still followed just at a more compact level. Shown below in Figure 5 is the final assembly of this Spring 2012 semester. The main objective of this design is reducing the amount of oxygen based hoses in order to make the plumbing more compact. In this set up the safety factor played a major role as mentioned above. New Mexico State University Spring 2012 Page 26

27 Figure 5: Rocket and Plumbing Assembly Figure 6 (below) shows the complete hybrid rocket inside the portable case. There is Styrofoam protecting individual components and consists of a tool bag with all tools required to setup and disassemble rocket. Items missing from the case that are needed to test include; Oxygen bottle and regulator, Safety glasses/ ear plugs, Sturdy table, C- Clamp (to attach test stand to table), Power extension cord, 3 quart inch open end wrench, Fire extinguisher, and Welders gloves New Mexico State University Spring 2012 Page 27

28 Figure 6: Hybrid Rocket in Portable Case New Mexico State University Spring 2012 Page 28

29 Facet 6 PROJECT AND DATA ANALYSIS Project Analysis Throughout the current semester all portions of this project have been completed. The redesign of the before mentioned items (Facet 4) have been accomplished. Below is a project and data analysis of the whole system, along with a description of one of the requirements that was unable to be accomplished. Below in Figure 1 is a picture of the test stand. This test stand consists of a platform load cell which measures the thrust of the rocket motor. The lever arms, at the front of the stand, each contain two ball bearings that are holding the allen screws in place. This allows the top plate to move with the rocket motor reducing the amount of friction. The allen screws on the right side of the top plate hold the rocket motor in place. Figure 2 shows the rocket motor with a top and bottom plate made out of aluminum. Aluminum was chosen to create a motor that was lightweight and it would allow the heat to dissipate faster than that of steel. The top plate was manufactured at the beginning of this semester, where the bottom plate was manufactured in the Fall 2011 term. The fuel being used is a clear extruded acrylic rod which lights by means of a hobby rocket fuse and oxygen. The nozzle is graphite and designed for a Mach 2 performance. This nozzle is the original nozzle NASA has provided. On each corner of the top and bottom plate are four aluminum rods. These four aluminum rods are what hold both the top and bottom plate and keep the fuel grain stable. Figure 1: Rocket Test Stand with a platform load cell. Figure 2: Rocket motor consisting of fuel grain and nozzle. The ignition system for this device was the most crucial part of this semester. One of the requirements given by NASA was to create a reusable ignition system. There were three ideas taken into account, each of which did not work, therefore this requirement was unable to be fulfilled. Currently, since time is very limited, it was decided that the original ignition system is what needs to be used at this time. This ignition requires a hobby rocket fuse that will light the acrylic, therefore the requirement for the reusable ignition system has not been met. New Mexico State University Spring 2012 Page 29

30 The electronics are all currently running off of one data acquisition box. These electronics include the pressure transducer, the flow controller, and the platform load cell. Devices such as the flow control read out box, a DC battery, and all the wiring are contained in an old power supply box, shown in Figure10. This box is used as a power supply and allows the different electronics to be plugged and uses a USB from the data acquisition box to gather data such as pressure, thrust, and oxygen flow and can be seen in Figure 11. The program which collects this data is known as LabVIEW. This program is able to control the amount of oxygen flow desired by means of a slider on the control panel and is also able to control the sample rate. It also, shows a graph for each of the data sets when the program is running. A smaller program was made to ignite the fuse by a push of a button. Figure 10: View of the inside the power supply. Figure 11: Complete power supply. Figure 12 shows a complete layout of the full system. Starting from the left side there is an oxygen tank connected to a regulator, which will allow the oxygen flow to enter through the system by a 2 foot steel braided oxygen rated hoses. The first piece seen in this set up is a manual valve; this is used to release the pressure once the system is shut off. This is followed by a solenoid valve which acts as the emergency shut off switch and will cut off the oxygen supply once the throttle is released. This throttle is sitting on top of the power supply box. The next device is the flow controller, followed by a pressure gauge which reads off the pressure in psi as the flow exits the flow controller. This then leads to a 6 inch steel braided hose connected by a quick connect for a fast and easy release to the cross section. This cross section consists of a pressure transducer at the opposite end of the steel braided hose and a fuse connected at the back end which leads into the connection of the rocket motor sitting on top of the test stand. New Mexico State University Spring 2012 Page 30

31 Figure 12: Layout of the Portable Hybrid Rocket. There were many redesigns and notable accomplishments completed over the course of these past two semesters. First, 23 of the 24 original requirements set by NASA were completed. This included the addition of the emergency shut-off subsystem along with the redesigning of the data acquisition and analysis package. Next, hardware such as the oxidizer supply system, test stand, and the engine top and bottom plates were redesigned and remanufactured to completion. Redesigns of other hardware components such as the graphite nozzle and data instrumentation have been completed, along with the case shown in Figure 13, which was designed by the students. This concludes the objectives achieved for designing a conveniently deployed Portable Hybrid Rocket. The final product includes a functioning portable hybrid rocket engine and test stand along with a fully automated system control and data analysis package that is safe to operate within its designed constraints. Figure 13: Completed case ready to be delivered. New Mexico State University Spring 2012 Page 31

32 For every test during this Spring 2012 semester, a test log was kept and an analysis of the data was ran using a Matlab program designed by one of the electrical engineers. The main goal for analyzing the data was to have a program which would be ran after every test. This is so that students would gain an educational uderstanding of what happens during the test. The three different measurements taken for every test include the flow of the oxygen, the thrust that the rocket produces, and the pressure readouts that is supplied by the oxygen. Shown below is an example of the data we get after each test and every test log for each test ran this semester. Calibration Numbers: Rocket Data Plot Example 1.) Thrust (N/v) -> N/v 2.) Pressure (psi/v) -> 6 psi/v 3.) Flow (slpm/v) -> 50 slpm/v Times (Start/End): 1.) Total samples = N = samples 2.) Sample rate = fs = 500 Hz 3.) Starting sample of ignition = si = (60 sec)*(sample rate = 500 Hz) = 30,000 4.) End sample = es = N = ) Time vector = t = [1/N: et/n: et] 6.) Start time = t(si) = 155 sec => sample 30,000 of time vector t 7.) End time = et = N/fs = 215 sec New Mexico State University Spring 2012 Page 32

33 Th ru st (N /V ) Pr es su re (p si/ Fl o w (sl p m/ Thrust Pressure Flow When looking at the plots you can see that they begin at 155 seconds, this is because the actual ignition of the rocket does not start until that time (the test lasts 60 seconds, so the end time is =215secs). New Mexico State University Spring 2012 Page 33

34 New Mexico State University Spring 2012 Page 34

35 New Mexico State University Spring 2012 Page 35

36 New Mexico State University Spring 2012 Page 36

37 New Mexico State University Spring 2012 Page 37

38 New Mexico State University Spring 2012 Page 38

39 New Mexico State University Spring 2012 Page 39