The Optimize Design And Length Of Periodic Fully Developed Section In Shell Side Of Trefoil-baffle Support Heat Exchanger

With the rapid development of the social economy, the energy question involvessociety’s each field, so it is extremely urgent to explore and develop new alternativeenergy. Trefoil-baffle support heat exchanger is the main heat transfer equipment inPWR nuclear island device. The performance of trefoil-baffle support heat exchangerhas direct impact on working performance and the reliability of whole nuclear powerunit. Based on numerical simulation and compared with the experimental results, thefollowing aspects of the trefoil-baffle support heat exchanger were discussed:（1）According to the experimental research of trefoil-baffle support heat exchanger,the model of the same size was built by simplified and was used to compare withexperimental model. The results show that the model is feasible, the conclusionprovide the reference for the design.（2）Velocity, pressure gradient and dimensionless temperature were used todetermination the length of periodic fully developed segment in shell-side. The resultsshow that the length range from375mm to1275mm, this mean that range from thesecond support plate to the last support plate. In the same flow rate, the velocity ofshell-side fluid in the support plate was obviously higher than others velocities. Thepressure gradient is increased with rising of shell-side Reynolds number, but thedimensionless temperature almost independent of shell-side Re.（3）The Periodic Whole Cross-section Computation Model’s structure optimizedesign was carried out, by orthogonal experimental design. The method of rangeanalysis and square variance analysis were adopted, also the single factor’s influenceon the index was analyzed. As for comprehensive performance coefficient/p,there is interaction between these factors. （4）Multivariate analysis of The “Periodic Whole Cross-section ComputationModel” was carried out, by SPSS using the method of least squares. Both thecorrelative equations of the heat transfer coefficient and pressure drop were deducedand tested.（5）The heat transfer performance optimization of trefoil-baffle support heatexchanger was carried out, by using Genetic Algorithm. Based on the single objectiveand multi-objective Genetic Algorithm, the five variables and the constraintconditions were determined to optimize the results of the objective functions,entransy dissipation number and total costs, by writing programs. The results showthat the effective degree of heat exchanger was increased, but the pump power andthe rate of heat capacity flow were reduced by optimization design. Pump power ofmulti-objective optimization was reduced about13.7%than that of single objectiveoptimization. Moreover, the Pareto solution has more flexibility than single objectivefunction optimization, it can be chosen by designer.