非平衡闪蒸启始阶段气液换热过程的理论与实验研究

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中图分类号：TK219文献标志码：A

DOI：10.7652/xjtuxb202508011 文章编号：0253-987X（2025）08-0112-10

Theoretical and Experimental Investigation of Gas-Liquid Heat Transfer During the Initial Stage of Non-Equilibrium Flash Evaporation

FENG Tianhuangrui，ZHANG Yin，LI Xiaoran，WU Weifeng School of Energy and Power Engineering，Xi'an Jiaotong University，Xi'an 71oo49，China

Abstract： To address the challnge in determining thermodynamic parameters of working mediums within the expansion chamber of triangular flash cycle systems， the heat transfer process between vapor and liquid phases during initial flash evaporation is investigated. An equivalent expansion test rig is established to simulate the flash evaporation process in a twophase expander chamber using water as the working medium，with high-speed photography employed to observe vapor-liquid phase transitions. A heat transfer model at the vapor-liquid interface is developed based on dimensionless parameter normalization and validated against experimental data under identical operating conditions. The results demonstrate that during the establishment of dynamic equilibrium between evaporation and exhaust in the flash chamber，the initial chamber pressure exhibits a V-shaped variation pattern，comprising three distinct stages ： rapid pressure drop，pressure recovery，and quasi-steady state;the proposed model achieves over 94% agreement with experimental measurements； increasing the initial liquid temperature enhances superheat degree and flash intensity：each 10∘C temperature rise leads to approximately 15% increase in maximum superheat and 20% to 30% improvement in flash rate;as the valve opening increases from 25% to 70% ， the flow area for flash vapor expands，causing the average pressure drop rate to rise from 54.73kPa/s to 122.47kPa/s . This results in increased temperature gradients within the liquid， elevated local superheat，and a nonlinear enhancement of flash rate from 0.38kg/s to 0.56kg/s . This research provides valuable references for the design and operational optimization of two-phase expanders in triangular flash cycle systems.

Keywords： flash evaporation; start stage; equivalent expansion; triangular flash vaporization cycle

在余热回收和海水淡化领域，以有机朗肯循环（ORC）为代表的中低温热源余热回收系统受到广泛关注[1]。（剩余15757字）