Plate-fin Heat Exchanger Performances Under Variable Medium Thermodynamic Properties

Research and development of plate-fin heat exchangers are reviewed. Using of the advantage analysis ,Fluent simulation, neural networks to analyze rectangular fin heat exchanger data from Fluent simulation, empirical equations of pressure drop and heat transfer are obtained. A multi-parameter input and output BP neural network is built, good consequence is predicted. Parameter fitting of heat exchanger fins is studied. Giving the partial differentiation and boundary conditions of constant property material and unmixed cross-flow plate-fin heat exchangers, Fourier transform is used to solve the equation. By introducing Laplace transform, Hofmann's solution is improved, analytical solution is expanded, variable thermodynamic properties are considered, and one mixed and other unmixed heat exchangr analytical solution is given. Using Bernoulli's equation, the correlation between local pressure drops of sudden contraction and sudden expansion and porosity is built. Using Re instead of j / f parameter and the Chaos iterative approach, the RK Shah plate-fin heat exchanger design process is improved. Using Fortran, distributed parameter model of plate-fin heat exchanger procedure is written, with which heat transfer with variable thermodynamic properties is studied, temperature field and Re gradient lines are gotten, and Fang number (Fn) is used to predict pressure drop with variouble thermodynamic properties.