Calculation of airflow using K-value

Calculation of fans in parallel Full pressure: Pt double = Pt single Static pressure: Pst double = Pt single Dynamic pressure: Pd double = Pd single Flow rate: Q double = Q single X 2 Noise: LwiA double = LwiA single + 3dB * Speed: n double = n single X 1.05...

Sound Pressure Level and Sound Power Level Conversion Free Sound Field: Lw=LP+20lg(r)+10.9dB Semi-Free Sound Field: Lw=LP+20lg(r)+7.9dB Reverberant Sound Field: Lw=LP+10lgV-10lgT-14dB Lw-Sound Power Level, dB...

Full pressure full pressure = static pressure + dynamic pressure outside the static pressure outside the static pressure △ P = Rm * L (1 + k) Pa where: Rm - unit length of the duct friction resistance loss, Pa / m; L - the furthest air supply duct length plus the furthest back to the mouth of the return air return duct length, m; k - the ratio of the local resistance loss and the friction resistance loss. k-ratio of local resistance loss to friction resistance loss....

As can be seen from the above figure, when the fan speed S is the same, the outlet wind speed V of the forward inclined fan will be much higher than that of the rear inclined fan, so if it is necessary to produce the same amount of air volume and pressure, the rear inclined fan needs to adopt a higher speed or increase the size of the fan. Therefore, small size, low speed and low noise are the advantages of the forward inclined fan over the rear inclined fan, but the efficiency of the rear inclined fan is...

The blades of a backward inclined fan rotate in a backward direction relative to the impeller, hence the name backward inclined fan. Backward inclined fans are suitable for relatively low air volume and high pressure conditions. Usually, the static pressure efficiency of the backward inclined fan can reach more than 70%, and the wing type impeller can reach 80%. The outlet wind speed of the backward inclined fan is lower, so compared with the forward inclined fan, to reach the same air volume, the rotational speed will be higher, and the impeller...

The blades of the forward inclined fan are bent forward relative to the impeller rotation, so it is called forward inclined fan The forward inclined fan is mostly used for relatively low rotational speed, large air volume, and low pressure working conditions. Usually, the selection pressure of the forward fan is not more than 1000Pa, and the static pressure efficiency is generally not more than 55% The outlet wind speed of the forward fan is higher, so it can obtain a larger air volume at a low rotational speed, and in general, the...

According to the type of impeller, centrifugal fans can be categorized into two types: forward-inclined and backward-inclined