Drag Reduction Mechanism And Energy Consumption Analysis Of Vacuum Pipeline Vehicle Suction System

As the development of the society and economy,cooperation and population movements in different regions become more and more frequent,so people put forward higher requirements for travel speed and efficiency.However,in the surface environment,due to the influence of dense atmospheric environment,it is difficult for ordinary vehicles to run faster than 400 km/h,so a high-speed,low-energy,safe and environmentally-friendly vacuum pipeline transportation system emerges as the times require.Because of the high-speed operation in narrow pipelines,a large amount of blocking air will accumulate in the front of the vehicle,resulting in the increase of aerodynamic drag.Therefore,it is necessary to study the aerodynamic characteristics of the vacuum pipeline transportation system.In order to avoid a large amount of air blocking in the front of the vehicle,resulting in the increase of aerodynamic drag and energy consumption,as well as the Kantrowitz limit phenomenon.A suction system is set up on the vehicle's head according to the principle of boundary layer suction of low-energy fluid,and the air silting in the head is transferred by active suction,so as to reduce the aerodynamic resistance and improve the running speed.Firstly,this article establishes a numerical model for the analysis and calculation of vacuum pipeline transportation system under low pressure environment,and studies the aerodynamic characteristics of vacuum pipeline traffic vehicles under different pipeline pressure and different operating speed.The study found that the aerodynamic drag is proportional to the pipe pressure and proportional to the square of the speed.Then a suction system is set up on the vehicle's head,and the aerodynamic drag and pressure between head and tail are taken as the main evaluation indexes to analyze and study the suction rate,suction port size and suction position of the suction system.It is found that the greater the pipeline pressure,the faster th e running speed,and the higher the mass flow rate when achieve the best effect of drag reduction;when the suction port is set in the maximum pressure area of the head,the blocking air can be sucked in time and effectively,so gets a better effect of drag reduction;the suction port is not as large as possible,when the suction port is too large,the streamline of the head is changed,and the flow of the head airflow is disturbed,so that the aerodynamic drag cannot be further reduced.After reasonably selecting parameters of suction system,a drag reduction effect of about 30% has been achieved.In order to verify the accuracy of parameter selection,the three-dimensional model is validated and analyzed,and the drag reduction effect is not less than 30%,which shows that the suction system is an effective drag reduction method.It is more valuable to achieve economical operation while reducing drag and increasing speed.Finally,this paper analyzes the energy consumption of the suction system under different pipeline pressure,different speed and different working conditions.It is found that under the optimum mass flow,the economy of the suction system is the best;under the same pressure,the faster the speed,the better the economy of the suction system;and at the same speed,the higher the pressure,the better the economy of the suction system;only when the critical economic speed is reached,the opening of the suction system is economical.This article mainly discusses the relationship between the aerodynamic drag of the vacuum pipeline vehicle and the pressure and speed.Research and analysis on the drag reduction effect,drag reduction mechanism and economy of the suction system,which obtain effective drag reduction and speed increase effect,as well as good economy.It shows that the research on drag reduction of suction system is of great significance and can provide some reference for the future research on drag reduction and speed increase of vacuum pipeline transportation system.