Two-phase flow heat transfer of propane vaporization in horizontal minichannels

Abstract

Experiments were performed on the convective boiling heat transfer in horizontal minichannels using propane. The test section was made of stainless steel tubes with inner diameters of 1.5 mm and 3.0 mm and lengths of 1000 mm and 2000 mm, respectively, and it was uniformly heated by applying an electric current directly to the tubes. Local heat transfer coefficients were obtained for a heat flux range of 5-20 kW m -2 , a mass flux range of 50-400 kg m -2 s -1 , saturation temperatures of 10, 5, and 0°C and quality ranges of up to 1.0. The nucleate boiling heat transfer contribution was predominant, particularly at the low quality region. Decreases in the heat transfer coefficient occurred at a lower vapor quality with a rise of heat flux and mass flux, and with a lower saturation temperature and inner tube diameter. Laminar flow appeared in the minichannel flows. A new boiling heat transfer coefficient correlation that is based on the superposition model for propane was developed with 8.27% mean deviation.

A general criterion for evaporative heat transfer in micro/mini-channels

“…These observations are both correct and simply refer to two different heat transfer regimes that can in fact simultaneously occur in different parts of the same heated channel. Lin et al [7], Choi et al [18,19], Diaz and Schmidt [20], Ong and Thome [24], and Pamitran et al [25] dominant at relatively high quality. We can also find that the nucleate-boiling-dominated mechanism represents dispersed bubble and confined bubble flow patterns in accordance with the flow regime definitions of Kew and Cornwell [29], whereas convectiondominated heat transfer is associated with the annular flow regime.…”

“…Table 1 lists the experimental data of two-phase heat transfer in micro/mini-channels, which covers the fluids of R12, R134a, R11, R123, water, CO 2 , R410a, R22, ethanol, R236fa, R245fa, and propane at various heat fluxes, mass fluxes, and qualities. There are two types of micro/mini-channel geometries: one is circular channels in highly conductive metal (copper, aluminum, stainless steel, or brass) [5][6][7][9][10][11][12][13][14][17][18][19][22][23][24][25], the other is rectangular channels in silicon or metal substrate [5,[7][8][15][16][20][21]. The latter can be 3-side or 4-side heated.…”

“…The latter can be 3-side or 4-side heated. Tests were conducted with single-channel [5][6][7][9][10][11][13][14][17][18][19][20][22][23][24][25] and multi-channel [8,12,[15][16]21] configurations.…”

Two-Phase Flow Boiling and Condensation Heat Transfer Characteristics of Natural Refrigerants: Review

“…Studies on the hydrocarbon mixture and comparison of several hydrocarbons with conventional refrigerants, such as R134a and R22 have been performed. The studies on the boiling heat transfer characteristics of propane (R290) were performed by Fernando et al, 38 Pamitran et al, 39 Choi et al, 40 Maqbool et al, 41 and Wang et al 42 Fernando et al 38 measured heat transfer coe±cients of propane in a vertically mounted multi-port minichannel heat exchanger. The heat transfer coe±cients increased with increase of heat°ux and mass°ux.…”

“…Pamitran et al39 and Choi et al40 performed boiling heat transfer experiments in horizontal minichannels with propane. The e®ects of heat°ux on heat transfer coe±cients were much dominant at the low quality and the e®ects of mass°ux were dominant at the high vapor quality.…”