The regulation of outlet valve of centrifugal fan is to change the characteristics of pipe network, not to change the characteristics of air conditioner fan. The range of air flow regulation is usually under all conditions under the rated performance curve of the fan. The regulating principle of the inlet air valve is the same as that of the outlet air valve when the pipe is arranged on the suction side of the fan; However, when the pipe is arranged on the exhaust side of the fan, it can change the performance curve of the fan by changing the inlet pressure of the fan, so the adjustment is economical.
In the selection of centrifugal fans, the user must first determine the three elements of the selection, that is, the flow rate, pressure and density of the gas in the working environment. The density is the most important factor in the selection process. If the density is not given, it is necessary to calculate or convert the density of the working gas according to the operating conditions of the centrifugal fan, such as altitude, local atmospheric pressure, working temperature and gas density.
After the three basic elements are determined, the specific rotation number of centrifugal fan should be calculated, which is because the calculation of specific rotation number is an important step in the selection process of fan, and is also the main basis for judging the selection of specific model of fan. According to the formula of calculating the conversion to the standard state of the fan and the specific rotation number, different specific rotation numbers can be obtained according to the different rotational speeds.
In this process, the performance curve is mainly determined according to the model of centrifugal fan. The performance curve is divided into dimensionality curve and dimensionless curve. The dimensionless curve is the basis for determining whether or not to meet the requirements of the scene, while the dimensionless curve is the basis for describing the characteristics of the fan, the dimensionality represents the particularity, and the dimensionless dimension represents the universality.https://www.jnblower.com/