Performance Analysis And Optimization Of Gas Heating Water Heater Based On Pin Fin Structure

With the development of Chinese society,Chinese people pay more and more attention to environmental protection and energy sustainable development.People pay more and more attention to the energy saving and emission reduction of fossil fuel combustion equipment.In this paper,the gas-fired heating hot water boiler with silicon aluminum heat exchanger is studied systematically.On the one hand,the emission and overall thermal efficiency of the boiler system are studied,on the other hand,the structure of silicon aluminum heat exchanger is analyzed and optimized.These works have important guiding significance for the production and application of gas heating hot water boiler with silicon aluminum heat exchanger.The layout of the heating hot water boiler in this paper belongs to the pin fin layout,which can be called the pin fin heat exchanger.In this paper,the physical model of pin fin heat exchanger is simplified and the calculation formula of heat transfer coefficient of pin fin heat exchanger is derived.According to the formula of heat transfer coefficient,the optimization direction of the structural parameters of the pin fin heat exchanger is obtained,which are diameter,height,longitudinal distance and transverse distance.Based on the experimental data of heat transfer and pressure drop of heat exchanger with pin fin structure in the flue gas side,the coefficients of the general correlation are obtained.According to the influencing factors(diameter,height,longitudinal distance and transverse distance)analyzed by heat transfer coefficient as decision variables,taking heat transfer coefficient and pressure drop as objective functions,NSGA-II genetic algorithm is used for optimization.Using TOPSIS decision-making method,the Pareto solution domain obtained by genetic algorithm is selected,the best individual is selected,and the best parameters of needle wing structure are obtained.According to the best individual selected,the numerical analysis method is used to study the distribution of temperature field and pressure field when the flow rate of flue gas changes in the pin fin heat exchanger.The velocity and temperature nephogram of the pin fin heat exchanger directly reflect the influence of relevant design and operation parameters on the performance of the heat exchanger,and adjust the arrangement structure of the pin fin in the areas with high temperature and high speed.In this paper,the influence of operation parameters on the condensation rate of gas-fired heating water heater is studied,and relevant empirical correlations are obtained.Then,the influence of different load,excess air coefficient and inlet water temperature on the thermal efficiency and emission of gas-fired heating water heater is studied.Finally,this paper takes the excess air coefficient,gas heat load,inlet water temperature and fan speed as design variables,takes thermal efficiency,nitrogen oxide and carbon monoxide as prediction values,and builds BP artificial neural network to predict the performance of gas heating furnace.