| "Made in China 2025" is the main direction of intelligent manufacturing,and the smart home is one of the hot spots of intelligent manufacturing.The most important component that influences the comfort is the air conditioner,the performance of which is directly affected by the performance of heat exchangers.And the most of the air conditioning heat exchangers adopt fin-and-tube heat exchangers for their advantages of compactness and high yield.Therefore,to realize the intelligent manufacturing of intelligent home,the whole cycle including design,process and operation of the fin-and-tube heat exchanger is required to meet the needs of intelligence,which includes the following three points: rapid design of the heat exchanger structure to meet performance requirements;intelligent generation of 3D heat exchanger drawings for the machining center to manufacture;real-time monitoring of heat exchanger performance.The design method of computer simulation has become the mainstream design method of heat exchangers for its rapid and efficient characteristics.The existing simulation software is able to build heat exchanger models,but the modeling of large heat exchangers needs a lot of time because of the large number of flow paths and complicated pipeline connections of large heat exchangers.And therefore the rapid design of flow path in the simulation software needs further study.There is no research on the intelligent generation of 3D model of air conditioner heat exchangers.As for real-time monitoring of heat exchanger performance in operation,the real-time monitoring of air conditioning heat exchanger still needs further research,and thus,this paper researched the above three aspects and achieved the following results:(1)A rapid design method of heat exchangers in simulation software is developed.At first,the mapping algorithm of flow paths in the heat exchanger is developed.By traversing the connecting pipe parameters in the flow path one by one,the positional relation between the original flow path and the mapping flow path is obtained,and the mapped flow path is generated automatically,so as to realize the function of arraying and copying flow paths.Then,multiple-select mechanism in the simulation software is developed.By combining the multiple-select mechanism with the mapping algorithm,the function of copying multiple flow paths is realized.The results show that the efficiency of heat exchangers design can be greatly improved by the usage of the function of the flow path copying and arraying in the simulation software.(2)A method of drawing three-dimensional graphs of heat exchangers by the simulation software is developed.At first,the mapping algorithm of changing the digraph which storages the structure of heat exchanger in simulation software into the position coordinates in the SolidWorks software is presented,and then SolidWorks invoking interface is developed in the simulation software by secondarily developing SolidWorks software.Finally,position coordinates is adopted by the API function of SolidWorks to realize the automatic drawing of heat exchangers in simulation software.The application results show that the simulation software of heat exchanger can significantly improve the efficiency of 3D drawing.(3)A method for on-line monitoring the performance of refrigeration system based on finite measurement points is developed.At first,a method of arranging measuring points based on finite temperature and pressure measuring points is proposed,which includes the temperature and pressure of the suction and discharge of the compressor,the liquid temperature of the condenser and so on.Then,the solving method of each performance parameter is developed by using system parameters,and the compressor mass flow rate is fitted in the polynomial form of the inlet and outlet pressure based on the theoretical model.Then the mass flow rate can be calculated by inlet and outlet pressure of compressor.With the calculated mass flow rate and heat loss,the refrigerating capacity can be obtained.The heat transfer quantity of condenser,the actual power of compressor and EER are calculated.The equation of the fan performance curve and the characteristic equation of the air side resistance of the heat exchanger can be used to deduce the air volume of the fan under different fan opening degree.Finally,through the fan performance curve equation and the characteristics of wind side resistance equation of heat exchangers,the fan volume is deduced.Compared with the measured values,the average deviation of the calculated performance parameters is less than 20%,which meets the requirements of real-time monitoring.Results show that the fast modeling function of heat exchangers developed in this paper can improve the modeling efficiency in the simulation software more than 8 times.Compared with the traditional method,the graphic automatic function of three-dimensional generation of heat exchangers can improve the drawing efficiency more than 5 times.The real-time detection method based on the limited measuring points developed in this paper can accurately predict the performance of refrigeration systems,and the maximum deviation between the parameters by the experimental method and fitting value is 18.91%,and the average maximum deviation is 13.77%. |
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