Abstract

The article elucidates characteristic features of heat transfer during rapid transfer of single-phase solution beyond the liquid-liquid spinodal. It also investigates particularities of the thermal response accompanying decay of unstable state. The objects of the study were aqueous solutions of polypropylene glycols and ethylene glycol monobutyl ether. Controlled pulsed heating of probe was applied, based on the thermal mode of probe temperature stabilization at a given temperature T ^st. The temperature stabilization stage lasted for 20 to 100 ms; the temperature T ^st was increased step by step from the initial value T ⁰ up to 673–773 K. The values of the instantaneous coefficient of heat transfer to pure components and their solutions were calculated from the primary data. At a certain degree of superheating, a temperature-threshold effect of heat transfer enhancement up to 2–3 times was found, which is associated with the decay of unstable state of the solution. The fundamental possibility was revealed for determination of approximation for the lateral and upper spinodal branches, reconstructed on the basis of the characteristic change in the response signals. The concentration of the solution was changed step by step in the zone of compositions lying under the liquid-liquid equilibrium line.

中文翻译：

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溶液不稳定态衰变强化传热

摘要

本文阐明了单相溶液在液-液旋节线以外的快速传递过程中传热的特征。它还研究了伴随不稳定状态衰减的热响应的特殊性。研究对象是聚丙二醇和乙二醇单丁醚的水溶液。基于在给定温度T ^st下探针温度稳定的热模式，应用探针的受控脉冲加热。温度稳定阶段持续20到100毫秒；温度T ^{st从初始值}T ⁰ 逐步升高 高达 673–773 K。根据原始数据计算了纯组分的瞬时传热系数及其解的值。在一定的过热度下，发现了高达2-3倍的传热增强的温度阈值效应，这与溶液不稳定状态的衰减有关。揭示了确定横向和上旋节线分支近似值的基本可能性，根据响应信号的特征变化重建。溶液的浓度在位于液-液平衡线以下的组成区域中逐步变化。