Flow Field Visualization of the Released Gas Flow from Pressurized Vessel

Amir Hossan

2019-2023

Bachelor in Mechanical Engineering

ABSTRACT

Nowadays, with the rapid growth of the fuel gas uses, gas explosion is a frequently occurrence all over the world. Due to gas related explosion and fire, every year people are facing several kinds of costs in term of financial amount, even sometimes unexpected death and that sets an alarming dimension to investigate the explosions of the flammable gas. When a pressurized vessel with flammable gas is accidently damaged, the gas will be released into the air and creates a high potential for explosion. In the previous investigation, the Gas-Release Operation system for Storage Safety (GROSS) has been constructed and operated to investigate the potential explosion risk of the released gas. In this study, the classical Schlieren imaging technique is used for flow field visualization of the releasing for analyzing the potential risk of an explosion. A camera has captured the Schlieren-images with 60 fps. Nitrogen gas is used to perform the experiment and two raptures are in the experiment to simulate damage on an LPG-tank with different sizes. The diameter of the rupture 1 & 2 is 8.12 mm & 57.39mm respectively. The results of the experiments show that the gas-release processes with the two different ruptures can be categorized into two types, continuous jet and blowdown depressurization, which indicate different potential of explosion risk. In the experiment with the rupture 1, the releasing gas flow presents a continuous jet. The pressure of the vessel decreased to atmospheric level within approximately 8 seconds and temperature drops near the rupture hole relatively higher which is around -60 °C. In contrast with rupture 2, the experiment produces a blowdown depressurization. The pressure of the vessel decreased rapidly to the atmosphere pressure within less than one second. The temperature has changed with a fluctuation and went to same as room temperature after 55 seconds. Here, rupture 2 produce shows a much higher a potential risk of explosion than rupture 1. Moreover, gas release from the both size of the ruptures shows turbulence flow.

Keywords: Schlieren Imaging, Flammable Gas, Continuous Jet, Blowdown Depressurization, Explosion.