Two-phase heat transfer to a refrigerant in a 1 mm diameter tube

A study of two-phase flow and heat transfer in a small tube of 1 mm internal diameter has been conducted experimentally as part of a wider study of boiling in small channels. R141b has been used as the working fluid. The boiling heat transfer in the small tube has been measured over a mass flux range of 300-2000 kg/m(2) s and heat flux range of 10-1150 kW/m(2). In this paper the boiling map for a mass velocity of 510 kg/m(2) s and heat flux of 18-72 kW/m(2) is discussed and the problems of determining heat transfer coefficients in small channels are highlighted. (C) 2000 Elsevier Science Ltd and IIR. All rights reserved.