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How to calculate the flow and pressure of high temperature fan

2019-04-23 16:49:07 zero

    How to calculate the flow rate and pressure of high-temperature fan selection? How to calculate the accurate answer? This is really a technical question. I believe this formula is difficult for many people. Some customers just know how much flow and air pressure their enterprises want to achieve, but they don't know how to calculate the air volume and model of high-temperature fan. If they are professional fan factory family members, they are asking customers to Calculate the result to select the model. When you calculate the high-temperature fan, you should pay attention to the correct formula to calculate the model. If there is a bit of calculation error, the following model selection will be wrong. The following Zibo centrifugal fan manufacturer will introduce how to calculate the corresponding formula in the selection of high-temperature fan:

 High temperature fan.png

1. Standard state: refers to the air pressure at the inlet of the fan P = 101325pa, temperature T = 20 ℃, relative humidity φ = 50%.


2. Specified state: refers to the air intake condition of high temperature fan. This includes the local atmospheric pressure or altitude, the pressure of the inlet gas, the temperature of the inlet gas, and the composition and volume percentage concentration of the inlet gas.


3. High temperature fan flow and flow coefficient


Flow: refers to the unit time flow through the fan inlet gas volume.


Expressed in Q, usually in m3 / h or m3 / min.


Discharge coefficient: φ = q / (900 π D22 × U2)


Where: φ: discharge coefficient Q: discharge, m3 / h


D2: impeller diameter, M


U2: linear velocity of impeller outer edge, M / S (U2 = π D2N / 60)


4. Total pressure and total pressure coefficient of high temperature fan:


High temperature fan total pressure: the difference between the total pressure on the fan outlet section and the total pressure on the inlet section. Expressed in PTF, commonly used unit: PA


Total pressure coefficient: ψ t = kpptf / ρ u22


Where, ψ T: total pressure coefficient Kp: compressibility correction coefficient PTF: Fan total pressure, PA ρ: gas density at fan inlet, kg / m ^ 3 U2: linear velocity of impeller outer edge, M / s


5. High temperature fan dynamic pressure: the pressure represented by kinetic energy of gas on the fan outlet section, expressed by PD. Unit: Pa


6. Static pressure of fan: the total pressure of fan minus the dynamic pressure of fan, expressed by PJ. Unit: Pa


7. Relationship among total pressure, static pressure and dynamic pressure of high temperature fan:


Total pressure of fan (PTF) = static pressure of fan (PJ) + dynamic pressure of fan (PD)


8. Gas density at fan inlet: gas density refers to the mass of gas per unit volume, expressed by ρ, commonly used unit: kg / m3


9. Calculation formula of gas density at the inlet of high temperature fan: ρ = P / RT


Where: P: absolute pressure at inlet, PA R: gas constant, J / kg · K. It is related to the type and composition of the gas.