Effect of converging diverging mixing duct geometric parameters on performance of circularly lobed nozzle ejector
At present,few studies are devoted to the effect of structural parameters of converging diverging mixing ducts on circularly lobed nozzle ejector.Therefore,several converging diverging mixing ducts with different geometric parameters were designed firstly,and an experimental study on the pumping performance of circularly lobed nozzle and circular nozzle exhaust-ejector scaled-down models was developed.The results showed that when the throat diameter and length of the mixing duct were smaller,the pumping ratio of the circular nozzle was higher than that of the lobed nozzle within lower main flow range,but the situation was reversed as the mass flow increased.When the throat diameter and length of the mixing duct were larger,under the condition of wall-attached main flow,the pumping ratio of the lobed nozzle was higher than that of the circular nozzle within the experimental mass flow range.With the increase of the mass flow,a maximum value of the pumping ratios appeared.Furthermore,as the throat diameter and length increased,the maximum value also gradually increased,and the maximum growth rate was 58.5％.Secondly,a numerical calculation model was established and verified by experimental data,with the error not more than 4.5％.The simulation results showed that the total pressure recovery coefficient increased as the throat diameter and length of the mixing duct increased.Therefore,larger mixing ducts throat diameter and length had an improved effect on flow loss.
converging diverging mixing ductscircularly lobed nozzlecircular nozzleexperiment and simulation of ejectorpumping performance
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