The calculation of kitchen exhaust air volume is the same as the elimination of harmful gases in factories and laboratories. All the harmful gases produced should be removed clean, which belongs to professional smoke extraction technology. So what is the exhaust air volume calculation content of the kitchen exhaust hood?
The calculation of smoke air volume should be based on the capture of all the hot gas produced, not just equal to a simple ventilation. According to the principle of fluid mechanics, the flow process of smoke inhalation and exhaust is explained, which is helpful to the analysis and comparison of calculation methods, and also helpful to the calculation and analysis of other types of smoke exhaust equipment.
Pressure travels at the speed of sound in the same way that sound does in air. The gas is sucked into the negative pressure area to form a flow, and a spherical isobaric surface is formed at the center of the negative pressure area, also known as the isobaric surface. On this isobaric surface, the pressure is equal, the pressure causes the airflow to flow at the same speed, and the streamline is everywhere perpendicular to the spherical isobaric surface.
In the isobaric surface with different radius, the spherical area is different and the flow rate is different. The flow through the spherical area is equal, that is, the flow rate is the same as that of the suction outlet. That is, a spherical isobaric surface is formed at the center of the negative pressure zone, and the flow rate is inversely proportional to the square of the distance from the center. Because the flow field is a spherical space, the velocity decays very fast.
Because the negative pressure of the exhaust vent in the exhaust hood forms an approximately spherical isobaric surface centered on the exhaust vent, the bucket exhaust hood has a downward cover to control the direction of pressure propagation, and the spherical isobaric surface is incomplete. The isobaric surface formed by negative pressure of rectangular cover of smoke exhaust hood can also be regarded as the isobaric surface synthesized by cylindrical isobaric surface of rectangular cover center line and hemispherical isobaric surface at both ends of smoke exhaust hood.
Because the transmission of pressure has the diffraction ability, the air on the side of the ji 'nan exhaust hood without the wall and the upper part of the exhaust hood will also mix with the smoke and enter the smoke hood. Therefore, the surrounding situation of the exhaust hood should be considered in the calculation. For example, whether the exhaust hood is surrounded by a wall or an open one, the isobaric surface area can be reduced by relying on the wall, the mixing of air can be reduced, and the efficiency of smoke exhaust can be improved.
The exhaust air volume calculation of the kitchen exhaust hood is explained here. If you have any questions about the exhaust hood, please come to the website www.staywellfit.com for consultation.