An experimental rig was set up to study the performance of a thermal storage unit using stearic acid as the heat storage medium. The unit mainly consists of an electrical heating rod and an outer tube, and the space between is an annulus that is filled with stearic acid. The thermal performance of the unit is measured, and the heat transfer characteristics of the melting processes of stearic acid are studied under different heat flux conditions to determine the influence of heat flux on the melting processes. A new type of fin is designed and fixed to the electrical heating rod to enhance the thermal response of the stearic acid. The experimental results show that the fin can improve the heat transfer of the melting process of the thermal storage unit greatly. The equivalent thermal conductivity of the PCM can be augmented by a factor up to 3. The analysis of the experimental results shows that the enhancement mechanism of the fin is attributed to its ability to improve both heat conduction and natural convection very effectively. The influences of the fin size and pitch on the enhancement are also studied and analyzed and it is found that these two parameters can both affect the thermal conductivity enhancement significantly.

The thermal and heat transfer characteristics of stearic acid during the solidification processes were investigated experimentally in a vertical annulus energy storage system. The temperature distribution and temperature variations with time at different radial positions during the freezing processes were obtained. The thermal characteristics of the stearic acid, including movement of the solid–liquid interface in the radial direction, and the effects of Reynolds number on the heat transfer parameters were studied. The heat flux was estimated by using a simple approximate model. A new copper fin was designed and fixed to the electrical heating rod to enhance the thermal conductivity of the stearic acid. The results show that the new fin can enhance both the conduction and the natural convection heat transfer of the PCM, and the enhancement factor during solidification is estimated to be as high as 250%. The effect of the fin width on the enhancement was also examined experimentally, and it is found that the fine fin usually produce more effective enhancement.

Melting in a finite slab with a second kind boundary condition is studied numerically in order to simulate the charging process of a thermal energy storage system. A dimensionless model is given, from which it is concluded that the main factors that influence the melting process are the dimensionless heating flux, the modified Stefan number, the relative thermal diffusivity and the relative thermal conductivity. The influence of preheating or solid subcooling is studied. It is found that though preheating does not have very important effects on the melting time, it does influence the interface marching velocity significantly. The melt fraction and the melting time are calculated extensively for various dimensionless numbers. The numerical results show that the ratio of the thermal conductivity of the solid to that of the liquid has little effect on the melting time, and the time for finishing melting can be expressed as a function of the dimensionless heating flux, the modified Stefan number and the relative thermal diffusivity, and the possible function form is suggested.

扬沸是油罐火灾中特有的灾害性燃烧现象。根据对油罐着火扬沸发生前传热机理的分析，给出了简化数学模型。利用该模型分析了水层温度响应过程，提出了着火初始阶段时间长度的概念，并给出其解析表达式，为通过实验整理经验关系式提供了明确形式。通过数值计算，还对燃烧速度、油罐表面冷却等因素进行了分析。结果表明，燃烧速度对扬沸发生时间影响最大，而油罐表面冷却并不能有效地延迟扬沸的发生。

对测量材料导热系数的热丝法的原理性误差进行了分析研究，结果表明，热丝几何半径和热容量所造成的误差必须进行修正。文中给出了一个简单实用的修正公式。本文还探索性地分析研究了被测介质初始温度分布不均匀对测量结果的影响。

通过对结晶垢结垢过程传热传质机理的分析，证明了垢层表面温度随时间的变化会对结垢过程产生重大影响。据此提出了考虑垢层表面温度变化的描述结垢过程的传热传质模型，对恒壁温和恒热流条件下的结垢过程进行了详尽的分析和讨论。结果表明，对恒壁温情况必须考虑垢层表面温度随时间的变化，这一变化是导致结垢过程渐近特性的重要原因之一；而对恒热流情况，垢层表面温度随时间的变化很小，可以忽略它所带来的对结垢过程的影响。与实验数据比较表明，模型预测是正确可靠的。

报道了固体颗粒对池沸腾换热表面结垢特性影响的实验研究结果。沸腾工质为CaSO4水溶液，换热表面材料为紫铜，固体颗粒是0.5～1mm的玻璃珠。实验结果表明，在平表面池沸腾条件下引入固体颗粒只能在较短的运行时间内起到强化换热的作用。当运行时间较长时，不仅不能强化换热，反而因结垢而使得换热恶化。

相变潜热随温度变化的变温固液相变过程进行了数值分析计算，重点分析了相变潜热随温度变化对相变过程的影响。结果表明，对于相变潜热随温度变化的相变过程，其主要影响因素仍然是Stefan数、相对导热系数、相对热扩散系数、相变温度宽度等基本无量纲数。尽管相变潜热随温度的变化会对相变过程造成一定的影响，但如果用相变温度范围内的平均潜热代替实际相变且视为常数，则可以较好地近似实际相变过程：由此不会给预测融化所需要的总时间带来明显的误差，而对温度分布的影响也很小，主要集中在液固过渡区内。

通过对有限容积法界面插值的分析，提出了一种较调和平均法更为直接、更为有效的用于计算控制容积法控制界面参数的插值方法，许给出了调和平均法失效的算例。数值算例表明，本文方法与Kirchhoff变换法相比具有相当的精度，但又不像Kirchhoff变换法那样需要完成大量的积分运算，计算工作量小，简单可靠。