Abstract
Experiments on the flow boiling heat transrer or HCFC123 and ammonia inside a internallv spirally grooved horizontal steel tube with a 12mm average inner diameter were performed. Experimental conditions of ammonia are 30 to 100 kg/(m^2.s) in mass velocity about 0.7 MPa in pressure, and () to 20 kW/m^2 in heat flux. The correlation for heat transfer coefficients from both fluids in the annular flow regime were developed based on the assumption that the heat transfer enhancement by the inner grooves on the heat transfer surface varies by mass velocity. Also the results in the separated flow regime could be correlated well using the present equation for the well wetted surface at bottom and the previously proposed correlation for the fluorocarbons on the thin liquid meniscus.
