| Due to its safety,reliability,no electricity,and easy installation,the annular slot ejector for gas dilution has received extensive attention in applications such as corner gas control in coal mining face.In this paper,a two-dimensional structural model is established for the problem of low performance of the annular slotted gas dilutionr reported in the current market.The numerical simulation method is used to study the influence parameters of the annular slot ejector for gas dilution to obtain the influence of the performance of the device,and the experimental verification of the performance of the optimized model.The main research contents include:(1)Mining annular slot ejector for gas dilution(BRWX-80)is selected as the research object.With Fluent numerical simulation software,two-dimensional injector structural model is constructed to simulate the overall process of gas flowing,blending and diffusing within annular injecting gas diluter.By simulation calculation of the internal flow field and based on aerodynamics,hydromechanics and other relevant theories,the influences of major parameters,including stagnation pressure ratio,Mach number,back pressure and mainstream pressure on the injection coefficients are analyzed and the distribution regularities of the internal flow field is revealed,which could provide theoretical support for parameter optimization of annular injector.(2)Based on the initial model of the annular slot ejector for gas dilution,the single element analysis method is used to change the structural parameter size of the ejector(mixing chamber length HL,diffusion chamber length KL,diffusion chamber angle ?,throat diameter d,and slit width e),in the range of the mainstream pressure of 0.3?0.7MPa,simulate the influence relationship of the ejector structural parameters on the ejector coefficient,and determine the reasonable structural parameters of the improved model,where HL=40mm,KL=360mm,?=6°,d=160 mm,e=0.1 mm.(3)Under the condition that the structural parameters of the ejector are changed at the same time,six groups of annular ejector structure models are established.The performance of the ejector under each model is simulated and the model is used in the range of 0.3?0.7MPa.The grey relational analysis method takes the ejector coefficient as the reference sequence and the structural parameters as the relevant factors.The importance order of the factors affecting the performance of the ejector is obtained,which is a>?>HL>d>KL.(4)Firstly,based on the numerical simulation results,an improved model of the annular slotted gas dilutionr was designed,and then the experimental system platform was built based on the annular slotted gas dilution optimizer model.The logarithmic linear measurement method was used to select the secondary control measurement.The flow inlet cross-section dynamic pressure is calculated,and the secondary inlet velocity and the ejector flow rate are calculated.At the same time,the gas vortex flowmeter is used to measure the mass flow rate of the compressed gas under the standard state,and the ejector coefficient of the improved model is obtained.Finally,the simulation and experimental results of the improved model are compared and analyzed.The results show that the simulation error meets the engineering requirements.In summary,based on the structural model of the BRWX-80 type annular slot ejector for gas dilution,the numerical simulation and experimental analysis method are used to analyze the influence of structural parameters and operating parameters on the ejector coefficient,and the influence is determined.The primary and secondary relationships of the ejector performance factors are designed and the improved model is designed.The research results have certain guiding significance for the optimization of the structural parameters of the annular injecting gas diluter. |
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