Effect of wall thickness on the end corrections of the extended inlet and outlet of a double-tuned expansion chamber

Study on applicability of end corrections of extended inlet and outlet of expansion chamber hydraulic noise suppressor

“…Acoustic domain of the hydraulic oil is discretized into a number of finite elements, and then the use of the Galerkin formulation for the acoustic system yields [1,2,10]:…”

“…Torregrosa et al applied the FEM to calculate the end corrections of the extended inlet and outlet of a coaxial expansion chamber muffler and studied the effects of diameter ratio for them [9]. Besides, Chaitanya and Munjal studied the effect of wall thickness of the inlet and outlet ducts [10]. Selamet and Ji used a three-dimensional (3D) analytical approach to analyze the end correction of a circular pipe connected with a circular asymmetric cavity [11].…”

“…Further, Kang and Ji analyzed the effects of chamber length, duct extension and diametric ratio on the end correction [12]. However, the focus of the existing literature [3][4][5][6][7][8][9][10][11][12] is on gas mufflers. No one has considered the higher-order mode effects for expansion chamber hydraulic suppressors with extended inlets and outlets.…”

Performance Analysis of Improved Vehicle Muffler

“…To the improvement of muffler, acoustic performance is mainly to improve transmission loss and aerodynamic performance is mainly to reduce back pressure, that can reduce the engine power loss and ensure fuel economy. It is important to choose the proper structure and to make the main parameters (such as length of inlet and outlet pipe of muffler [12]), when the noise attenuation is large and the power loss is small. In view that the reactive muffler in the high-frequency effect is poor, and dissipative muffler in the high frequency effect is very good, we use impedance com-posite design to improve the overall muffler effect.…”

Optimal topology of reactive muffler achieving target transmission loss values: Design and experiment

“…Researchers contributing to the former have investigated the effects of the dimensions and shape of mufflers on the TL curves by using the TL formula starting from the acoustic wave equation. Munjal et al [4][5][6] used transfer matrix techniques to calculate the TL value and to tune the lengths of the extended inlet/outlet inside the expansion chamber. Selamet et al [7][8][9] investigated the effect of the length of the muffler on acoustical attenuation performance and tuned the lengths of vertical/horizontal partitions inside the expansion chamber.…”