An Improved Gas Leakage Model and Research on the Leakage Field Strength Characteristics of R290 in Limited Space

Abstract

Some alternative refrigerants with excellent environmental performance often have different flammable limits. When refrigerant leaks, the external space may have a certain explosion risk if the refrigerant is not diffused timely. To understand the leakage and diffusion characteristics of the refrigerant, an improved gas leakage model was proposed in this paper, and the accuracy verification of the improved model was developed. Based on the above works, taking R290 as the research object, the variation law of the field strength between the leaked gas and external space and the influence of different initial leakage pressures on the field strength characteristics were analyzed. The simulation results showed that when the initial leakage pressure was 2 MPa, the R290 gas entered the external space as a supersonic jet, the gas underwent continuous expansion and compression processes in the near-field area and a Mach disk was formed within the flow area. During this process, parameters, such as the temperature, pressure, velocity and density of the leaked R290 gas, changed dramatically, and then the gas gradually returned to room temperature and normal pressure through interaction with the external space. The flammable area formed by the leaked R290 was mainly concentrated in the local flow area below the leak hole, and the existence of the Mach disk caused the R290 high concentration area to increase. With the increase in the initial leakage pressure, the distance from the Mach disk to the leak hole and the circumferential diameter of the Mach disk increased, and the flammable area increased slightly in the horizontal direction, whereas the flammable area increased significantly in the vertical direction.

The Characteristics of Acoustic Emissions Due to Gas Leaks in Circular Cylinders: A Theoretical and Experimental Investigation

“…According to the mathematical model of hole leakage [21][22][23], the characteristics of gas flow, such as mass flow rate (Q) and mean flow velocity in the leak hole, can be divided into sonic flow and subsonic flow according to the critical pressure ratio (CPR)…”

“…respectively, where ξ is given by Equation (23). Finally, the displacement fields generated by the gas leakage can be summarized as follows…”

“…In this study, we determined the FRS from the reported date [20]. where 𝑢′𝑣′ is assumed to be the mean value of the product of 𝑣 𝑣 , and According to the mathematical model of hole leakage [21][22][23], the characteristics gas flow, such as mass flow rate (Q) and mean flow velocity in the leak hole, can be vided into sonic flow and subsonic flow according to the critical pressure ratio (CPR)…”

Potential for Energy Utilization of Air Compression Section Using an Open Absorption Refrigeration System

“…Though they provide a valuable reference, these literature studies mainly focused on the thermodynamic characteristics of ORC itself, rather than the thermodynamic coupling principles between the ORC and the air compression process. The energy conversion from waste heat to electricity has been demonstrated to be an efficient way for energy utilization; however, some study results also show that the ORC power generation efficiency is significantly affected by the compression heat grade and its volatility [18], and may suffer from refrigerant leakage [19].…”

Characteristics of Acoustic Emission due to Gas Leak in Circular Cylinder: Theoretical and Experimental Investigation

“…In this study, we determined the FRS from the reported date [20]. where 𝑢′𝑣′ is assumed to be the mean value of the product of 𝑣 𝑣 , and According to the mathematical model of hole leakage [21][22][23], the characteristics gas flow, such as mass flow rate (Q) and mean flow velocity in the leak hole, can be vided into sonic flow and subsonic flow according to the critical pressure ratio (CPR)…”