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Final Report

Final Report. Viren Bhanot. Work Done. Rotary compressor – Its working and calculations Small Experiment Line Bypass Heater C alibration Heat Balance Report Accumulator Dry-Out testing Accumulator Cooling Power measurements CMS Pixel Upgrade User’s Manual for Building 158.

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Final Report

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  1. Final Report Viren Bhanot

  2. Work Done • Rotary compressor – Its working and calculations • Small Experiment Line • Bypass Heater Calibration • Heat Balance Report • Accumulator Dry-Out testing • Accumulator Cooling Power measurements • CMS Pixel Upgrade • User’s Manual for Building 158

  3. Rotary Compressor Sanyo Compressor • Model no.: C-C140L5 • Dedicated for CO2 • Two-Stage compression • Pressure rating of 90 bar (outlet, 2nd stage)

  4. Matlab Compressor Calculations

  5. Small Experiment Line • 250W Cartridge Heater • Swagelok Fittings • Concentric Heat Exchanger after Mass Flow Meter • Actuators for Metering Valves

  6. Heater Selection • 250 W heater required • Cartridge, insertion heater for direct heating • Inlet to heater perpendicular to its length • Flow development analysed for selection • Hydrodynamic and Thermodynamic flow development • Low watt density required

  7. Heater Selection Correlations Used: • Hausen • Stephan • Shah/London • Flow Development • Fully Developed • Thermodynamically developing, Hydrodynamically developed • Simultaneously developing

  8. Heater Selection Specifications: • WatlowFirerod Cartridge Heater • Ф-3/8”, Length – 7” • Power - 250 W • Watt Density – 5 W/cm2 • 4” No-heat zone • Epoxy Seals to protect from moisture

  9. Swagelok Fittings • Heater mounted on reducer union • Inlet through Welding Tee fitting • Tube inner dia = 1/2”, heater dia = 3/8” • Line between mass flow meter and metering valve in a concentric internal heat exchanger. • Whole Assembly Welded Together

  10. CAD Model

  11. Heater Assembly

  12. Actuator • Electrical Actuator for Swagelok metering valves Two companies discovered: • Hanbayinc. (Canada) • Grotec (Germany) • Actuator ordered from Hanbay (cost ~ $1500)

  13. Bypass Heater Calibration • Bypass Heater (2 kW) performance not satisfactory • Virtually no heating at low powers, then sudden overheating at medium-high powers • Output power not equal to power requested through PVSS • Heater controlled through phase angle controller (inexpensive way of controlling heater) • “Span” setting of heater too narrow. Corrected.

  14. Bypass Heater Calibration • Tests performed to measure heater power and compare it against input power (through PVSS) • System run in single phase to measure enthalpy using Pressure and Temperature. • Power o/p = Enthalpy Change x Massflow Rate • Pressure, temperature measured across internal heat exchanger. • Output power found to be not equal to input power

  15. Bypass Heater Calibration

  16. Bypass Heater Calibration • Phase Angle Controller chops up the sine-wave signal (4-20 mA) linear with time, instead of linear with output power • Mustapha prepared MATLAB and PVSS programs to correctly calculate output power to match input power. • New logic incorporated into PVSS by Lukasz. Works perfectly, and has been tested.

  17. Heat Balance • Heater Calibration tests expanded to give overview of heat balance for entire system. • Heat addition/extraction measured to get an idea of system performance • Compressor data also included Parameters measured • Preq • Qpump • Qheater • Qin • Qcond • Qcomp

  18. Heat Balance

  19. Heat Balance

  20. Heat Balance Conclusions drawn: • Up until 1100W, the readings are reliable. • Readings above 1100W are unreliable due to premature boiling of CO2 inside the tubes. • Offset between requested power and power measured is due to heat added by the pump and surroundings. • Compressor cooling capacity is lower than expected (this data is already 2 months old)

  21. Accumulator Dry-Out Testing • Accumulator heater in thermo-syphon configuration • During start-up, accumulator heated for long time • At higher vapor pressure, higher vapor density. • At higher density, lower convective currents • Risk of dry-out, heater melting.

  22. Accumulator Dry-Out Testing • A parameter called Thermal Resistance used to calculate dry-out thresholds • Accumulator heated for long periods with 250, 500, 750, 900 and 1000W power • Rthcalculated for all data points, and plotted against accumulator saturation temperature. • Combined graph for all readings plotted

  23. Accumulator Dry-Out Testing

  24. Accumulator Dry-Out Testing Conclusions drawn: • At 250W Heater Power, dry-out is not witnessed. • Higher the heater power, lower the saturation temperature at which dry-out occurs. • Some unexplained bumps are observed at higher powers, through sudden, steep rises and falls in the values of Thermal Resistance

  25. Accumulator Cooling Power • Tests done to measure cooling power in accumulator • It was expected that cooling at 100% valve opening should match heating at 100% heater power (1 kW) • This was not the case • Some cooling power lost because cooling spiral passes through liquid CO2.

  26. Accumulator Cooling Power • Accumulator cooled and then heated at specific rates. For example, 50% CV1105 valve opening corresponds to 50% heater power, 500W • Slopes of cooling and heating measured. • Cooling slope observed to be less than heating slope. • Since slope unequal, this method not enough to determine cooling power

  27. Accumulator Cooling Power

  28. Accumulator Cooling Power • Rough estimate obtained by plotting Heater’s power versus the value ‘dp/dt’ (change in pressure per unit time) • dp/dt values of cooling spiral superimposed on heating graph. • This gives rough but useful estimate of cooling capacity.

  29. Accumulator Cooling Power Cooling Power Measured:

  30. Accumulator Cooling Power Conclusions: • Cooling power does not correspond to its respective heating power. • The maximum cooling power available is only 740W. • The cooling power at 25% valve opening is not a quarter of the full cooling power. This is due to the inertia of the fluid. • Cooling Power is not completely linear over the entire range.

  31. CMS Pixel Upgrade • CMS Pixel layout being discussed with various iterations proposed. • Latest proposal (at that time) was simulated to measure the fluid temperature and pressure drop. Results were compared with Bart’s results (with his global calculator) • Joao’s calculator was used in Matlab, and simulations with Friedel and Chisholm correlations. • The simulation results were similar to, but not exactly the same as Bart’s own simulations.

  32. CMS Pixel Upgrade

  33. CMS Pixel Upgrade

  34. User’s Manual • The eventual aim of project was to prepare User Manual to allow external researchers (Belle, SLAC, IBL) to use the system without distracting Bart, Lukasz or Joao! • The manual is about 60 pages long and will hopefully be used by someone in the future.

  35. Thank You

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