Local, experimental heat transfer coefficients have been obtained for boiling refrigerant flowing up and across a tube bundle segment representing a full flooded evaporator tube bundle. R-134a data with a structured enhanced boiling tube are available. This tube has reentrant cavities designed for higher saturation pressure refrigerants. The refrigerant enters at 15% vapor quality and exits at nearly 100% vapor in order to simulate an actual evaporator bundle. Both heat flux, 2607 to 10,427 Btu/h·ft2 (8224 to 32,893 W/m2 ), and oil content, 0% to 12% (by weight), are varied; the mass flux is not an independent variable but determined by the heat flux. Local tube and bulk fluid temperatures are measured directly, by thermocouples, to calculate the refrigerant-side heat transfer coefficients. The bundle segment saturation temperature setpoint (taken at the top of the tube bundle) is 40°F (4.4°C).
Units: Dual
Citation: Symposium, ASHRAE Transactions, vol. 106, pt. 1
Product Details
- Published:
- 2000
- Number of Pages:
- 6
- File Size:
- 1 file , 170 KB
- Product Code(s):
- D-7375
