Effects of oil on boiling of replacement refrigerants flowing normal to a tube bundle--part II: R-134a

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 h...

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Bibliographic Details
Main Authors: Tatara, Robert A, Payvar, Parviz
Format: Conference Proceeding
Language:English
Subjects:
Evaporators
Heat flux
Heat transfer coefficients
Mass transfer
Refrigerants
Online Access:Get full text
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Summary: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 times ft super(2) (8224 to 32,893 W/m super(2)), 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 degree F (4.4 degree C).
ISSN:0001-2505