CRYOGENIC COOLING SYSTEMS Dr. Hezlin Ashraf-Ball Chief Project Engineer

Transcription

1 CRYOGENIC COOLING SYSTEMS Dr. Hezlin Ashraf-Ball Chief Project Engineer 19 th may nd HEXAG Meeting Newcastle University

2 Oswald Consultancy Ltd 2

3 Oswald Bespoke Heat Exchangers We specialize in: Novel heat exchanger design and development Design of system (not just about the components) We can supply: heat exchangers complete heat exchanger systems, heat exchanger design support Excel heat exchanger thermal performance models We have developed our own computer models to assess thermal performance 3

4 Cooling Application 4

5 Cryogenic Cooling System Cryogenic Cooling Systems 1. Control system a. Rate of cooling b. Duratherm temperature c. Nitrogen exhaust temperature d. Fuel temperature 2. Pumping systems a. Duratherm circulation gear pump b. Duratherm test chamber circulation centrifugal magnetic driven pump 3. Intermediate fluid reservoir a. Pressure relieve valve 4. LN2 Duratherm heat exchanger ( 2-off) a. Copper spiral heat exchanger b. Cryogenic solenoid valves flow control 5. Bund Full detailed design in CATIA V5 5

6 Controlled Cooling according to ARP 1401 Standard What is ARP 1401? Fuel preparation procedures and icing tests for aircraft fuel system and components are proposed herein as a recommended practice to be used in the aircraft industry for fixed wing aircraft and their operational environment only. not engine 6

7 Simple Flow Diagram Cooling System + Fuel HX Cryogenic Cooling System Fuel HX Altitude Chamber Testing Facility 7

8 System Layout Cooling System + Fuel HX Cryogenic Cooling System Altitude Chamber Testing Facility Fuel Heat Exchanger Aircraft pipes and test rigs Fuel Test Tank 8

9 P& ID Cooling System + Fuel HX Altitude Chamber Testing Facility 9

10 Thermal and Mechanical Design 10

11 Copper Heat Exchanger Multipitch Spiral (N2-Duratherm) We designed the heat exchanger using our proprietary heat exchanger model Concept and detailed design performed in CATIA Intermediate fluid heat transfer coefficient calculated using Dittus-Boelter inside tube correlations (Re ~16,000) heat transfer coefficient for gaseous nitrogrn calculated from first principle based on in-line tube banks Zukauskas correlation (Re~5700) Pr Pr w 1/4 Nu = hd Nu = CRe n Pr 0.36 k Nitrogen boiling heat transfer coefficient obtained from NASA showing film boiling region We completed the mechanical design We organised the heat exchanger fabrication using local engineering company 11

12 Copper Heat Exchanger Multipitch Spiral LN2-Duratherm 12

13 Copper Heat Exchanger Multipitch Spiral LN2-Duratherm 13

14 Heat Exchanger Design Multipass Plain Tube Bundle (Stainless Steel 304) 14 We designed the heat exchanger using our proprietary heat exchanger model Fuel heat transfer coefficient calculated from first principle based on Zukauskas staggered tube banks correlation Inside tube heat transfer coefficient calculated using Dittus-Boelter (Re~4000) Fuel heat transfer coefficient was determined based on agitation rate within the tank limited agitation and temperature difference forcing higher surface area requirement Plain surface tube was chosen to ensure little or no fuel waxing on the surface We subcontract the fabrication to Serck Heat Exchange

15 Control System Design 15

16 Control System Layout Single electrical connection point of 400V, 50Hz, 3P+E+N which should be fed from an RCD protected 16A supply. All external areas are connected to Earth All front panel controls are low voltage and isolated through a 30mA residual current device RCCD, minimising shock risk to personnel Functionality is provided by a programmable Schneider Electric Twido range micro PLC 16

17 Pumping System Design 17

18 Power (kw) Pressure (bar) Velocity (m/s) Pressure (bar) Pressure Drop and Velocity (IHES) P drop-1 Pass Velocity-1 Pass P Drop-2 Pass Velocity -2 Pass Pumping Duty Requirements Pressure Drop and Velocity (BHE) Pump Sizing Pipe external diameter (mm) P Drop - 2 Pass P Drop-4 Pass P drop- 8 Pass Pipe external diameter (mm) SH Velocity = 1.7m/s SH P Drop= 0.19bar SUPERHEATER Boiler Tube Diameter = 28mm Boiler Tube Length = 19m Boiler Velocity = 1.7m/s Boiler P Drop= 0.28bar BOILER IHES Bend losses = 0.18bar Circuit losses = 0.02bar Circuit Diameter = 42mm MINOR LOSSES P M P M BHE Tube Diameter = 28mm BHE Tube Length = 53m BHE No of Pass = 2 BHE Velocity = 3.5m/s BHE P Drop= 2.7bar BHE IHES Bend losses = 0.18bar Circuit losses = 0.02bar Circuit Diameter = 42mm MINOR LOSSES SH Tube Diameter= 28mm SH Tube Length = 13m SH Velocity = 1.7m/s SH P Drop= 0.19bar SUPERHEATER Boiler Tube Diameter = 28mm Boiler Tube Length = 19m Boiler Velocity = 1.7m/s Boiler P Drop= 0.28bar BHE Tube Diameter = 28mm BHE Tube Length = 53m BHE No of Pass = 2 BHE Velocity = 3.5m/s BHE P Drop= 2.7bar BHE LN2 Total P Loss = 0.87bar IHES Mass Flow = 0.8kg/s IHES I.F. Tank BHE Total P Loss = 2.92bar BHE Mass Flow = 3.3kg/s BHE BOILER IHES Bend losses = 0.18bar Circuit losses = 0.02bar Circuit Diameter = 42mm IHES Bend losses = 0.18bar Circuit losses = 0.02bar Circuit Diameter = 42mm 3 Shaft Power IHES BHE MINOR LOSSES P M P M MINOR LOSSES I.F. Tank LN2 Total P Loss = 0.87bar IHES Mass Flow = 0.8kg/s IHES BHE Total P Loss = 2.92bar BHE Mass Flow = 3.3kg/s BHE Pipe external diameter (mm) Shaft Power 3 IHES BHE

19 Pumping Duty Requirements Pump Sizing 19

20 Performance Test 20

21 Factory Acceptance Test Cooling Requirement 25kW The performnace of the system were tested during the Factory Acceptance test at our workshop in Nuneaton 1. Control system demonstrates controlled cooling to achieve more than ~25kW cooling as per requirement (heat loss was ignored) 2. Target of -55degC was achieved and PID tuning demonstates withing +/- 1degC overshoot (within requirement) 3. Nitrogen exhaust temperatures are used for efficient control of liquid nitrogen use 21

22 CE Marking 22

23 CE Marking Oswald referred to Machinery Directive for the purpose of conformity assessment for the IHES cart We have followed the prompt list given in machinery directive (1998L0037 EN ): An assembly of linked parts or components, at least one of which moves, with the appropriate actuators, control and power circuits, etc., joined together for a specific application, in particular for the processing, treatment, moving or packaging of a material. 23

24 Any questions? 24