Open Access

ARTICLE

Experimental Study on Flow Boiling Characteristics of Low-GWP Fluid R1234yf in Microchannels Heat Sink

Ying Zhang^1,2, Chao Dang^1,2,*, Zhiqiang Zhang^1,2

1 Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale, Beijing, 100044, China
2 Institute of Thermal Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, 100044, China

* Corresponding Author: Chao Dang. Email:

(This article belongs to the Special Issue: Fluid Flow, Heat and Mass Transfer within Novel Cooling Structures)

Frontiers in Heat and Mass Transfer 2025, 23(4), 1215-1242. https://doi.org/10.32604/fhmt.2025.067373

Received 01 May 2025; Accepted 16 June 2025; Issue published 29 August 2025

Abstract

In this study, the flow boiling characteristics of R1234yf in parallel microchannels were experimentally investigated. The experiments were conducted with heat flux from 0 to 550 kW/m², mass flux of 434, 727, and 1015 kg/(m² s), saturation temperatures of 293, 298, and 303 K, and inlet sub-cooling of 5, 10, and 15 K. The analysis of the experimental results provides the following conclusions: a reduced mass flux and lower subcooling correspond to a diminished degree of superheat at the boiling inception wall; conversely, an elevated saturation temperature results in a reduced amount of superheat at the boiling inception wall. Furthermore, an increase in sub-cooling and saturation temperature will enhance heat transfer efficiency. The wall temperature is mostly influenced by variations in saturation temperature and is minimally related to changes in mass flux and subcooling degree. An increase in mass flux results in a greater pressure drop attributed to heightened frictional pressure loss. The variation in pressure drop with respect to sub-cooling is minimal, while an increased saturation temperature correlates with a reduced pressure drop due to the formation of smaller bubbles and lowered frictional pressure loss at high saturation pressures. This study thoroughly examines and summarizes the effects of mass flow rate, saturation temperature, and subcooling on the flow-boiling heat transfer and pressure drop characteristics of R1234yf. Furthermore, the new correlation has 93.42% of the predicted values fall within a 15% mean absolute error, exhibiting a mean absolute error of 5.75%. It provides a superior method for predicting the flow-boiling heat transfer coefficients of R1234yf in the heat sink of parallel microchannels compared to existing correlations.

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Keywords

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