The goal of the present research is to investigate the feasibility of incorporating a liquid spring in a semi-active suspension system for use in heavy off-road vehicles. A compact compressible magneto-rheological (MR) fluid damper–liquid spring (CMRFD–LS) with high spring rate is designed, developed and tested. Compressible MR fluids with liquid spring and variable damping characteristics are used. These fluids can offer unique functions in reducing the volume/weight of vehicle struts and improving vehicle dynamic stability and safety. The proposed device consists of a cylinder and piston–rod arrangement with an internal annular MR fluid valve. The internal pressures in the chambers on either side of the piston develop the spring force, while the pressure difference across the MR valve produces the damping force, when the fluid flows through the MR valve. Harmonic characterization of the CMRFD–LS is performed and the force–displacement results are presented. A fluid-mechanics based model is also developed to predict the performance of the system at different operating conditions and compared to the experimental results. Good agreement between the experimental results and theoretical predictions has been achieved.
Thrust augmentation in rocket engines using secondary injection in the diverging part of a nozzle is an innovative extension of after burners. This technique finds application in single stage to orbit propulsion devices, where the nozzle has to work at varying ambient pressures. Experimental and numerical studies have been conducted with varying cross flow and injection conditions to analyse the performance augmentation in a 2D nozzle. Schlieren images and wall pressure data are obtained from the experiment. Simulations are conducted using a HLLC scheme based finite volume solver. A detailed description of flow physics resulting due to the introduction of sonic angled jet into expanding supersonic flow is presented. It is found that the injection angle, pressure and main flow pressure have notable influence in the performance of the nozzle.
In this study a compact compressible magneto-rheological (MR) fluid damper-liquid spring (CMRFD-LS) with high spring rate is designed, developed and tested. The proposed device consists of a cylinder and piston-rod arrangement, with an annular MR fluid valve. The internal pressures in the chambers on either side of the piston develop the spring force, while the pressure difference across the MR valve produces the damping force, when the fluid flows through the MR valve. A fluid mechanics-based model is conducted to predict the behavior of the damper device under sinusoidal input. The device is studied under oscillatory vibrations for various frequencies and applied magnetic fields. The experimental results are in good agreement with the theoretical predictions.
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