管内流动传热传质的熵产分析

Entropy Generation Analysis of Combined Heat and Mass Transfer Phenomena in Tube Flow

本文基于不可逆过程热力学的基本概念,导出了管内流动热、质同时传递过程的熵产率的一般表达式,推导中考虑了由于存在传热温差、传质化学势差及流体粘性阻力造成的不可逆性。当质量传递趋于零时,由该式得到的仅考虑温差及流体粘性的不可逆性时管内流动传热过程熵产率计算式与文献[3]提供的一致。由该一般式导得了一定条件下光滑圆管内充分发展的系统与壁面进行热、质交换的熵产率计算式。通过求熵产率极小可帮助确定基于第二定律分析的优化运行条件。

In this paper, a general expression is obtained for the entropy generation of the combined convective heat and mass transfer in tube flow. This expression, based on the principle of irreversible thermodynamics, accounts for irreversibilities due to the presence of heat transfer across a finite temperature difference, mass transfer across a finite difference in chemical potential of a species, and flow friction. In the limit of zero mass transfer, the expression becomes identical to that one comes from literature [3]. The general expression is applied to such a problem that the exchanging of heat and a chemical species between that wall and the full developed convective flow is considered. After minimizing the entropy generation, it is possible to help define the optimum operating conditions.