1. Tracker Thermal Control System TTCS Progress at Sun Yat-sen University Feb. 1, 2006, CERN Geneva Modeling: SS Lu, ZC Huang, DQ Mo, Y Chen EM test: TX Li, KH Guo, WJ Xiao, NQ Pei, XH Sun, ZW Pan, JF Ding, KL Yu Electronics: JQ Ni, XH Jiang, D Zhang, ZX Wang, CP Tang, GC Feng, YH Huang, Mechanics: XM Qi, XH Diao, GY Chen, SS Zheng by ZH He

2. Tracker Thermal Control System 2 Outline TTCS Power Budget Issue (SYSU/NLR) TTCS Test Bed (SYSU) TTCB Structure Analysis (SYSU) TTCE Status (SYSU/MIT/INFN)

3. Tracker Thermal Control System 3 TTCS Power Budget Issues TTCS power budget definition 125W (with about 70W beyond TTCS power budget) was needed to avoid CO2 from freezing in the coldest case, as simulation showed; Attempt to reduce this power is made by improving the temperature uniformity on the radiator; Current status –Almost no extra power is needed (for primary loop) but with small margin; –For a reasonable margin of 10K, about 25W extra power might be needed rarely.

4. Tracker Thermal Control System 4 Model development tree ZC Huang

5. Tracker Thermal Control System 5 General view of the loop for cmdv1.3 ZC Huang

6. Tracker Thermal Control System 6 General view of the loop for cmv1.0 DC Mo & ZC Huang General view of the loop for cmv1.0 DC Mo & ZC Huang

7. Tracker Thermal Control System 7 Main difference VersionCmdv1.3Cmv1.0 Main description common model of NLR and SYSU, draft version1.2 Loop built by SYSU, but other thermal model are the same as cmdv1.2 VolumeIncorrectcorrect AccumulatorBoundaryTank, which has limit volume of 1.1 L. Evaporator length The top and bottom Evaporator have the same length. For each, the feed line is 4.5m, the Evapor part is 9m, and return line is 3.5m. The top and bottom Evaporator have the different length. For top, the feed line and the return line are both 2.5m. For bottom, the feed line and the return line are both 1.0m. Evaporator attached to the tracker Total length: 0.405m + 2.2 m + 0.405m + 2.5m + 0.324m + 1.4m + 0.324m + 1.45m = 9.0 m., which length in red is the part attach to the tracker. Total length: 2*3.14*0.405m + 2*3.14*0.405m + 2*3.14*0.324m + 2*3.14*0.324m = 9.0 m. The total length both attach to the tracker. That in red is the part attach to big ring, while that in blue to the small ring. Feed line and return line in Rad The feed lines for both ram side and wake side are the same, 4.45m. The return lines for both ram side and wake side are 4.5m. And there is 1.0m connect the return line and joint point for each side. The feed line and return line for Ram side are 4.41m. For wake side, the feed line and return are 2.01m. Converge point The Ram side, wake side and the tube which connect Accumulator and loop are converge in one point (Junc1 here). The Ram side and wake side joint in one point (Junc 80). From the point, there is a line 0.25m long connects to the point (Junc 10 here) where Acc. connects to the loop.

8. Tracker Thermal Control System 8 b-75_0_0-15_cold for cmdv1.2 (with AF=1.32732e-6m 2, di`=1.3mm)

9. Tracker Thermal Control System 9 b-75_0_0-15_cold for cmdv1.3 (with di=2.6mm)

10. Tracker Thermal Control System 10 Reverse the flow direction of the condensers Original flow direction Reversed flow direction

11. Tracker Thermal Control System 11 Results of Reverse flow in two different models (primary loop) cases model Setpoint /k Subcooling /K liquid length/% xl of condenser inlet pressure drop/mbar heater RamWakeloopcondenser B+75-15-20-15Cmv1.02880~5.50~806~910.3~0.6511~856246~371No B+75-15_0-15Cmv1.02883.3~12.531~9085~950.3~0.45450~530210~250No B+75-15_0-15Cmdv1.3288 0.6~13.00~9178~93 0.33~0.49 498~644272~390 No B-75_0_0-15Cmv1.025810.6~11.6~92.6 ~0.32700320 50W on TTCB HX B-75_0_0-15Cmdv1.325817.6~20.94~9693~96 0.16~0.23 437~620233~31240W Flow rate=2g/s

12. Tracker Thermal Control System 12 RAM condenser cold area 424140393837 4336 443132333435 4530 462928272625 4724 481920212223 4918 501716151413 5112 527891011 536 5454321 424140393837 4336 443132333435 4530 462928272625 4724 481920212223 4918 501716151413 5112 527891011 536 5454321 -55  C

13. Tracker Thermal Control System 13 Temperature along the condenser pipes Cold case of B-75 0 0-15 Original with 125W Reversed with 40W (or less) Hot case of B+75-15-20-15

14. Tracker Thermal Control System 14 Reversed flow (with 40W)  T~20K Original flow (with 125W)  T~40K

15. Tracker Thermal Control System 15 T along the tracker lumps, top evaporator Max dT=0.14K for hot case Max dT=0.45K for cold case

16. Tracker Thermal Control System 16 Temperature distribution of hybrids layers Case: B-75_0_0-15_cold

17. Tracker Thermal Control System 17 Temperature distribution of hybrids layers II Case: B+75-15_0-15_hot

18. Tracker Thermal Control System 18 Average temperature of hybrid layers Hybrids12345678 hot T/K291.2294.2295.9298.3 295.8294.1291.0 cold T/K261.5264.8266.4268.8 266.4264.8261.5 This meets the Requirement by Tracker

19. Tracker Thermal Control System 19 Brief summary for uniformity Radiator is more uniform after reversing the flow direction. –Reduced heating power to avoid freezing –No big effect to the hot case. –Making the radiator working more efficiently More detail check is still needed for the models.

20. Tracker Thermal Control System 20 TTCS Power Budget Issues Summary (I) Improving the temperature uniformity in the condensers and radiators, e.g., by reversing the flow direction of CO2 in the condenser, is very helpful for reducing the heating power to avoid CO2 from freezing in the condensers.

21. Tracker Thermal Control System 21 TTCS Power Budget Issues Summary (II) TTCS power budget should be reconfigured. Suggestion: –Accumulator heater size should be reconfigured, (18W instead of 12.5W), in a price of a little less stable accumulator control; –Or heat leak should be readjusted from the accumulator to the loop; –A preheater is sized to 5W ; –An anti-frozen heater of 40W is added, preferentially to the coldest point of the condenser. Tracker hybrid power budget shared by TTCS in some extreme cases is proposed. –Considering Tracker hybrids may fail, less than 144W from the Tracker together with the present TTCS power budget is then not enough to avoid CO2 freezing.

22. Tracker Thermal Control System 22 Next Actions for thermal simulation Providing a draft description of the model before the Feb. 15 th for model checking. Checking of fluid part. (Feb 15 th ) Checking of reducing the radiator. (Feb. 20 th ) Checking of post processing (Feb. 30 th ) Simulation for secondary loop (March 30 th )

23. Tracker Thermal Control System 23 TTCS Test Bed Loop is built up, waiting for main components –Pump, Accumulator, Condenser, HX Leak test showed that less than 0.3 bar drop for 24 hours at the pressure of 50 bars.

24. Tracker Thermal Control System 24

25. Tracker Thermal Control System 25 An optical approach is under development for CO2 contact angle measurement CCD camera Protection wall Measurement of contact angle of CO2 on stainless steel surface.doc

26. Tracker Thermal Control System 26 TTCB Structure Analysis FEA meets safety requirement. TTCB_Structure Analysis_SYSU_I-deasV11_result_Jan2006.doc ‎

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