| The steam pipe network is an important facility for industrial and residential heating.In the process of steam pipe network transmission,unreasonable steam parameters will cause large economic losses,but the optimization of the pipe network operation can reduce the loss.Accurate hydraulic and thermal calculation of the steam pipe network is an important basis for the optimization of the pipe network operation,and it can provide an important reference for the operation optimization.In this paper,a hybrid model for hydraulic and thermal calculation of steam pipes is established based on the flow and heat transfer mechanism of steam transport and data-driven models.Then,based on the hybrid modeling and calculation of steam pipes,the hydraulic and thermal calculation method and the steam supply parameter calculation method for branch steam network are proposed,and the corresponding calculation software is developed.The main research contents include:Firstly,based on the steam flow and heat transfer mechanism in the pipeline,a mathematical model for the hydraulic-thermal coupling calculation of the steam pipeline was established.The mathematical model is solved numerically by the fourth-order Runge-Kutta formula,and the iterative method is combined to realize the hydraulic-thermal coupling calculation of the steam pipeline.It is verified by example calculation that the hydraulic-thermal coupling calculation method of steam pipe has higher accuracy than single hydraulic calculation and thermal calculation.Secondly,the hydraulic-thermal coupling calculation of the steam pipe is used as the mechanism model.A data-driven model of the mechanism error is established based on the historical operating data of the actual pipes.Among them,the data-driven model applies the kernel extreme learning machine optimized by the genetic algorithm to build a prediction model to predict the mechanism error,and then corrects the results of the hydraulic-thermal coupling calculation to improve the calculation accuracy.Comparing the calculation results of the example with the calculation results of the hydraulic-thermal coupling calculation,it is proved that the hybrid modeling calculation of the steam pipeline has higher calculation accuracy.Then,based on the hybrid model of the steam pipe,the hydraulic and thermal calculation method of the branch steam pipe network is proposed,and the corresponding calculation method of the steam supply parameters is proposed.The calculation results show that the method has high accuracy.The calculation results verify the effectiveness of the method when the user’s heating demand is known.Finally,based on the hydraulic and thermal calculation method of branch steam network proposed in this paper,C # and MATLAB language were used to develop the hydraulic and thermal calculation software of branch network.This software can realize functions such as pipe network line drawing,pipe network input,pipe network calculation,result output saving,and steam supply parameter calculation.It has high industrial application value and provides guidance for the reformation design and operation optimization of heating pipe network. |
