Core Models Reconstruction Of Refrigeration System For Simulation And Corresponding Simplified Models

In simulation process of refrigeration system, there is always a contradiction between precision and speed. In order to acquire high accuracy, we must build up relatively complicated models and corresponding programs. The elements amount adopted in distributed models should usually be larger than 200 if we want to acquire steady calculation results. Therefore, it will take us long time to accomplish simulation, especially for condensers. It is not a matter as models for single components. But when the models used in system simulation, the problem become apparent. So, it is necessary to simplify the models.Typical theories have been verified in traditional simulation methods. Compared to pure dark-box models, digital models show it strong control capability in qualitative trend. In that case, we can combine typical digital models with ANN. We introduce ANN to realize quantitative simplifying. In this course, ANN is used simply as a function approach tool. In other words, at fist we build up accurate models, and then seek for the corresponding simplified models as substitutions. We can enhance the simulation speed about 2~3 orders of magnitude while keeping qualitative accuracy.Based on the extensive literature review, this thesis rebuilds new components models suiting for system simulation. This thesis adopts approximate integral method and built up new algorithm procedure. Then, on assumption of one dimension reflux in heat exchangers, the thesis rebuild up models of condensers and evaporators. At last, the author dissects the hidden digital problems in given models and corrects qualitative errors which are uneasy to perceive in typical models. What's more, the author brings up the corresponding resolving projects.The author built up simplified models corresponding to distributed parameters models utilizing ANN. By optimizing input and output parameters, the author seek rational analyzing relationship in two-phase region. At last, the simplified models have apparently enhanced the simulation speed while keeping acceptable accuracy. It is a good step to advance to practical utility.As components models, the simplified models of capillary tube acquire high approximation and those of heat exchangers can also be viewed as rational because their deviation from the distributed parameters models are in the span of control. But, what have to be mentioned is that we will adventure into amplified deviation while we directly adopt the simplified models to system simulation. Therefore, the work...