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本文建立了耗散均匀分布原则(EoED):在给定热负荷和换热面积条件下,当局部耗散率在换热器中均匀分布时,总的耗散率取得最小值.并且证明了当传热系数不固定时,耗散均匀分布所得出的总耗散率小于温差均匀分布所得出的总耗散率,而有效度大于温差均匀分布的结果.如果假设换热系数固定,则耗散均匀分布等价于冷热流体的温差均匀分布.发现用熵产均匀分布原则和耗散均匀分布原则对换热器进行优化得出的熵产和耗散不相同.本文从理论上分析了熵产最小法与耗散最小法的适用范围:前者用于换热器的优化是基于使做功能力损失最小,而后者没有涉及到做功过程.并举例验证了熵产最小法与耗散最小法的区别,计算结果表明熵产数不适用于不同换热器间性能的比较,因为它直接依赖于流体的出入口温度;而耗散数不直接依赖于流体的出入口温度,因此,更适合作为不同换热器之间性能比较的标准.
In this paper, the principle of dissipative uniform distribution (EoED) is established: when the local dissipation rate is uniformly distributed in the heat exchanger under the conditions of heat load and heat transfer area, the total dissipation rate is minimized, When the heat transfer coefficient is not fixed, the dissipation of the uniform distribution of dissipation is less than the total dissipation rate of uniform temperature distribution, and the effectiveness is greater than the uniform temperature distribution results. If the assumption that the heat transfer coefficient is fixed, the consumption The uniform distribution of the dispersion is equivalent to the uniform distribution of the temperature difference between the cooling fluid and the cooling fluid. It is found that the entropy generation and the dissipation obtained by the principle of even distribution of entropy and the principle of uniform distribution of dissipation are different. In this paper, The entropy production minimum method and dissipation minimum method are applicable to the former: the former is used to optimize the heat exchanger based on minimizing the loss of work capacity, while the latter does not involve the work process. The results show that the entropy production is not suitable for the comparison of the performance of different heat exchangers because it directly depends on the temperature of the fluid inlet and outlet; while the dissipation number does not directly depend on the fluid inlet and outlet temperature, so it is more suitable for Standard Performance comparison between the different heat exchangers.