总压形式的能量方程与热阻问题

Energy Equation Expressed by Total Pressure and the Problem of Thermal Restriction

本文根据热力学第二定律的熵方程和稳定流的能量方程导出了用总压表示的一维定常流的能量方程。这是不同于稳定流能量方程（以焓表示的能量方程）和伯努利方程（机械能形式的能量方程或以压强位能表示的能量方程）；的另一种形式的能量方程。这一方程给出了热量、功量和熵产等因素对于气流总压的影响。特别是这一方程给出了热阻是一般流动情况下（不限于等截面加热管流和等压加热流动）的普遍现象的证明。文中第二部分给出了关于热阻的物理意义的定量分析。

The energy equation of one dimensional steady flow expressed by total pressure is derived on the basis of the second law of thermodynamics and the steady flow energy equations which is another kind of energy equations different from the steady flow energy equation(energy equation expressed by enthalpy) and the Bernoulli equation(energyequation in the form of machinery energy or energy equation expressed by pressure potential energy). This energy equation demonstrates the influence of heat, work and entropygeneration on flow total pressure, and proves that the thermal restriction is a common phenomenon(not limited to heated tube flow at constant area or at constant pressure)for onedimensional steady flow.A quantitative analysis of the physical significance of thermal restriction is given in the second Part of the Paper.