Study On Monolithic Muffler Performance Of Train Air-Conditioning Duct

The noise of ventilation and air conditioning system is one main source of train indoor noise. Nowdays installing Muffler in air conditioning duct is a great effective method for reducing noise, which generates two aspects of impact on air conditioning system. On one hand, the Muffler may reduce noise, on the other hand it can also increase air resistance. And when we choose the muffler, we should consider these two factors. So a detailed study on the muffler performance and flow field is very important.This article simulates the monolithic muffler performance and flow field with CFD and SYSNOISE, and gets the velocity and pressure inside the muffler and internal acoustic pressure distribution. Also I do the measurement on the test-bed of train air-conditioning duct and verify the simulation results correctness and rationality.With the simulation and test, this article analysis four factors including airflow velocity,sound insulation board thickness and slice, muffler length which influence flow field and the muffler performance.. This can provide some approaches and basis for the muffler design and selection.Finally, with the noise limit of train indoor and The SWL of conditioning unit noise, I improve the design of Muffler model by simulation software and calculate the muffler performance and flow field. Results show that after the improvement, the muffler can well meet the requirements of design, so the results verify the feasibility of the scheme.