After the gas alarm detector installed, how to detect the real gas concentration exactly?In addition to ensuring the quality of gas monitoring equipment, it is also necessary to ensure the impact of the external environment on the gas.What factors affect the diffusion of gas leakage?
Here is some brif introduction:
Wind direction determines the main direction of the leakage cloud.Wind speed affects the diffusion speed of the leakage gas cloud and the dilution speed of the air. The higher the wind speed, the stronger the atmospheric turbulence, the stronger the dilution effect of the air, and the stronger the transport effect of the wind.Generally speaking, when the wind speed is 1 meter to 5 meters per second, it is conducive to the diffusion of the leakage gas cloud and the danger area is larger.The higher the wind speed, the lower the concentration of the leakage gas on the ground.
Atmospheric stability is an index to evaluate the degree of vertical convection in the air layer.The more stable the atmosphere is, the more difficult it is for the leakage cloud to dissipate to the upper air, and to spread close to the surface.The more unstable the atmosphere, the stronger the vertical convective movement of the air, and the faster the leakage cloud dissipates.
Temperature or solar radiation mainly affect the diffusion of the leakage gas by affecting the vertical convection of the atmosphere.High atmospheric humidity is not conducive to the diffusion of leakage clouds.
The terrain and objects on the ground will change the diffusion speed and direction of the leaked gas cloud. The leakage cloud in the low-lying area of the ground is easy to stay. Buildings, trees and so on will strengthen the turbulence degree of the surface atmosphere, thus increasing the dilution effect of the air, while open and flat terrain, lakes and so on are the opposite. In low buildings, densely populated areas or green areas, the leakage gas cloud is not easy to spread; in high-rise buildings, it has a blocking effect, and the gas cloud will pass quickly from both sides with high wind speed.
When the location of leakage source is high, the vertical distance of leakage gas diffusion to the ground is large. Under the same leakage source intensity and meteorological conditions, the gas concentration at the same distance of diffusion to the ground will be reduced. If the gas is ejected upward and leaks, the leaking gas has the initial momentum upward, and its effect is like increasing the position of the leak source.
Compared with the air density, the leakage gas density is larger or smaller, which shows that gravity or buoyancy is the main role in diffusion. The gravity effect leads to its decrease, the ground concentration increases, and the downward trend will be weakened by the continuous dilution of air. The buoyancy effect causes the leakage gas to rise at the initial stage of diffusion, the ground concentration decreases, and the rising trend weakens after being continuously diluted by air. For the leaked high temperature gas, its buoyancy is affected by the temperature. When it is cooled to the atmospheric temperature, the buoyancy will be lost.