Decreasing of Profile Air Drag to the Train Movement Inside the Tube Transport

Abstract

Background: The movement of the train in an insulated space with the natural atmospheric pressure is accompanied by energy losses for unproductive work to overcome the profile air drag from the front and rear surfaces of the vehicle. At the same time, there is also a considerable increase of energy costs for overcoming the growing force of oncoming air drag. In order to exclude these energy losses, it is proposed to organize synchronous and volume-balanced pumping of air from the front part of the tube transport and injection of the air into the back part of the tube transport.
 Aim: To develop a method of organising air exchange inside the tube transport, which will ensure the reduction of air resistance to the movement of the train.
 Methods: The proposed developments are based on well-known national and foreign designs of high-speed tube transport systems, the results of a comparative analysis of tube transport with varying degrees of air pumping (backing vacuum and hard vacuum), taking into account the experience of redistributing the residual air volume in the Hyperloop and TransPod tube transport systems. The operating parameters of the compressor units that pump air into the internal cavity of the tube when the train is in motion is regulated on the basis of process models of gas dynamics.
 Results: A new method and device has been developed for reducing the air drag to the movement of the train by forced air exchange, which provides for the redistribution of air from the front to the rear of the transport tube relative to the vehicle travel direction. For the air redistribution, the external air exchange unit, consisting of air ducts, compressor units, gate valves, and air collectors is used. The process of external air exchange takes place only when the vehicle is in motion, for the movement of the vehicle no prior air exhaust is required. The air redistribution is controlled taking into account the speed of the train, its location in the tube, the design features of the tunnel and vehicle. The speed of the train for each segment of the speed section is normalised depending on the actual performance of the components of the air exchange system. Modes of operation of the compressor units must ensure synchronous redistribution of air from the front to the rear of the tube. The movement of a vehicle along a tube with normal atmospheric pressure in the internal cavity provides conditions for the safe transportation of goods and passengers.
 Conclusion: The developed method is designed to reduce the force of air resistance when the train is in motion inside the airtight tube without creating vacuum. The presented developments have good prospects for use in projects of high-speed transport systems of both underground and underwater designs.