Experimental Research And Numerical Simulation Of Power Generation For The Kinetic Energy Of Ventilation Air Methane

With the increasingly serious energy and environmental problems,it is imperative to save energy and reduce emissions in the process of industrial production.China is a big country of coal production and consumption.Starting from mine ventilation and energy saving,this paper mainly recyles and utilizes the kinetic energy of ventilation air methane at the outlet of mine fan diffuser.With the help of the current rapidly developing wind power generation technology,the experimental research is carried out on the design of power generation device for the kinetic energy of ventilation air methane.Combined with the method of numerical simulation,the structure of the device is optimized to achieve high effective power without affecting the normal ventilation of the ventilator.Based on the analysis of mine ventilation theory,wind power generation technology and gas jet theory,the complex diffuser structure is simplified into an equivalent cone in the design of the experimental device.A small three-blade horizontal axis wind turbine is used to convert kinetic energy into electrical energy recovery.And the collector structure is arranged at the front of the wind wheel to gather the ventilation air methane in the shape of a radial cone.It is suggested that optimizing the collector structure can increase the kinetic energy recovery efficiency.A simple conical collector is used in the experimental study.For?=16°/n=2 and?=16°/n=2.5 two kinds of equivalent conical diffusers,the starting state and working state of the wind turbine system under the inlet condition of four kinds of concentrators with dispersed structural parameters are studied.By analyzing the change of effective power generated at different distances,it is found that the device can work when the outlet wind speed of the residual flow pipe exceeds 1.8m/s.In normal operation,the phenomenon of effective power cascading distribution will occur,and the critical value L₀ in the barrier-free space is analyzed to be at least 4D_i?D_i is the inlet diameter of the diffuser?.Then,the effective power distribution cloud chart generated by a total of 24kinds of collector inlet conditions when L₀ is 4D_i and 5D_i is analyzed and studied in detail,and the high-power area with better response energy recovery efficiency is divided.Thus,the corresponding structure parameters of the collector are determined.At the same time,it is found that the distribution of diffuser's section enlargement coefficient is greatly different when it is changed.It is necessary to optimize the structure of conical collector because it is disturbed by the flow stability and experimental error.Finally,the internal flow field characteristics of the wind turbine system under the conditions of conical,circular and conical arc-shaped collector inlet are compared through numerical simulation.The velocity field,pressure field and vortex core area are analyzed in detail.It is found that the use of arc-shaped collector can make the airflow introduced into the wind wheel more uniform.The hindrance of the wind wheel to the incoming flow will also be reduced.No large vortices are generated on the rear side of the wind wheel.It can also effectively reduce noise.Wind wheel rotation stability is higher.The kinetic energy recovery efficiency can be further improved.