Mechanical and Aerospace Engineering

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https://hdl.handle.net/20.500.14540/110

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Browsing Mechanical and Aerospace Engineering by Advisor "Bhattarai, Nawaraj"

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    BUILD AND TEST A SMALL SCALE LIQUID ROCKET ENGINE
    (I.O.E, 2024-03) Paudel, Bijay; Sah, Dhaneshwar; Das, Dipak; Teli, Pritam Sah; Bhattarai, Nawaraj
    A liquid rocket engine is a type of propulsion system that uses liquid propellants, typically a fuel and an oxidizer, stored separately in tanks and then mixed and burned in a combustion chamber to produce thrust. Liquid rocket engines are widely used in various space exploration missions, satellite launches, and military applications due to their high performance and controllability. In this paper the components of a liquid rocket engine i.e nozzle, combustion chamber and fuel injector were designed and tested. Two fuels LPG and kerosene were combusted with gaseous oxygen to generate thrust. The components were simulated in ANSYS to test their performance. Pressure fed system was adopted to pressurize kerosene and LPG didn’t needed to be pressurized as it was already stored under pressure. Multiple test results were recorded and exhaust plume was analyzed. The thrust of magnitude 12N and 30N was measured in two tests and in other tests only exhaust plume was analyzed. Both the tests had to stopped midway due to chamber and injector failure due to high temperature produced in chamber. The yellow flame was observed in the exhaust plume which is caused by the glow of hot unburnt carbon particles produced due to incomplete combustion. So, further works on materials, manufacturing process and cooling is required.
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    Burst Strength Analysis of an LPG Cylinder using Experiment Data and Numerical Simulation
    (I.O.E, 2024-06) Yadav, Chandra Bhushan; Bhattarai, Nawaraj
    The research focuses on assessing the burst strength of the 14.2 Kg LPG cylinders for which the model is prepared according to Nepal and Indian Standards. 2.61 mm is chosen as the thickness of the LPG cylinder for which the minimum internal pressure is calculated using the ASME BPVC Section VIII, Division 1 and Nepal Standard Code using the yield strength as the allowable stress limit. The yield and ultimate tensile strength are obtained from the uniaxial tensile tests, while burst pressure is obtained from the hydrostatic pressure burst test. The test conducted on 9 different LPG cylinder samples resulted in an average yield strength, ultimate tensile strength and burst pressure of 283.879, 421.045 and 8.72 MPa respectively. The analytical burst pressure as per shell theory obtained is 6.98 MPa. Numerical simulation as per ASME BPVC Section VIII, Division 2, Part 5 yields burst pressure of 7.0014, 7.506713, and 8.421 MPa from Elastic, Limit Load and Elastic Plastic analysis respectively with, elastic plastic analysis considered most realistic approach. Since LPG cylinders are symmetrical about the longitudinal axis, axisymmetric 2D analysis is performed.