FLOW BOILING IN HORIZONTAL TUBES - PART 2 - NEW HEAT-TRANSFER DATA FOR 5 REFRIGERANTS

A summary of a comprehensive experimental study on flow boiling heat t ransfer is presented for five refrigerants (R134a, R123, R402A, R404A, and R502) evaporating inside plain, horizontal, copper tube test sect ions. The test data were obtained for both 12.00 mm and 10.92 mm diame ters using hot water as the heating source. Besides confirming known t rends in flow boiling heat transfer data as a function of test variabl es, it was also proven that the hear flux level at the dryout point at the top of the tube in annular flow has a very significant downstream effect on heat transfer coefficients in the annular flow regime with partial dryout.