The entropy generation of two immiscible fluids is investigated in a conjugate heat transfer system. The velocity and temperature fields are analytically obtained by solving the momentum and energy conservation equations. These analytical solutions are used to calculate the local and total entropy generation rates. Based on the entropy generation minimization (EGM), the total entropy generation of two-layer thermal flow system can be minimized by using the method of single variable optimization. Compared with the classical single-layer thermal flow system, the effects of viscosity ratio, thermal conductivity ratio and density ratio between upper and bottom fluids on the total entropy generation have been given special attention. Result shows that the total entropy generation can be minimized for the specific values of physical parameter ratio when the other parameters keep constant. Besides, it is also found that the total entropy generation of two immiscible fluids can be smaller than that of single fluid. This implies that the irreversible losses can be reduced in the present two-layer thermal flow system. And this reduction of irreversible losses can be helpful in improving the thermal performance of system. The present study is aimed at achieving a theoretical prediction to choose beforehand the appropriate types and heights of two immiscible fluids.

在共轭传热系统中研究了两种不混溶流体的熵产生。速度场和温度场是通过求解动量和能量守恒方程解析得到的。这些解析解用于计算局部和总熵生成率。基于熵生成最小化（EGM），可以使用单变量优化的方法来最小化两层热流系统的总熵生成。与经典的单层热流系统相比，上下层流体的粘度比、导热系数和密度比对总熵产生的影响得到了特别的关注。结果表明，当其他参数保持恒定时，对于特定的物理参数比值，总熵产生可以最小化。此外，还发现两种不混溶流体的总熵产生可以小于单一流体的总熵。这意味着在目前的两层热流系统中可以减少不可逆损失。这种不可逆损耗的减少有助于提高系统的热性能。本研究旨在实现理论预测，预先选择两种不混溶流体的适当类型和高度。这意味着在目前的两层热流系统中可以减少不可逆损失。这种不可逆损耗的减少有助于提高系统的热性能。本研究旨在实现理论预测，预先选择两种不混溶流体的适当类型和高度。这意味着在目前的两层热流系统中可以减少不可逆损失。这种不可逆损耗的减少有助于提高系统的热性能。本研究旨在实现理论预测，预先选择两种不混溶流体的适当类型和高度。