離心通風機的選型對于該風機來說是重要的一環，因為選型的正確與否關系到離心通風機能否發揮出最大效能，產生最大工作效率。那如何對其合理進行選型呢？下面小編就來解答這個問題，給讀者一些參考性的指導與建議，分析如下。
The selection of centrifugal fans is an important part of the fan, as the correctness of the selection is related to whether the centrifugal fan can achieve maximum efficiency and produce maximum working efficiency. How to make a reasonable selection for it? Below, the editor will answer this question and provide readers with some reference guidance and suggestions. The analysis is as follows.
選型第一階段：
The first stage of selection:
離心通風機要選型，首先要確定氣體的流量、壓力、密度，這是離心通風機選型過程的三要素，具體為：
To select a centrifugal fan, the first step is to determine the gas flow rate, pressure, and density. These are the three elements of the centrifugal fan selection process, specifically:
密度是選型過程中最為關鍵的第一要素，若未給定密度則需根據風機的工況環境，如海拔、當地大氣壓、工作溫度、氣體的標密來計算或換算出工況氣體的密度。
Density is the most crucial first element in the selection process. If density is not given, the density of the working gas needs to be calculated or converted based on the operating environment of the fan, such as altitude, local atmospheric pressure, working temperature, and gas density.
壓力是風機選型的第二要素，根據給定或計算出的工況密度，將工況壓力換算為風機標準狀態下壓力。如風機帶進氣箱或消聲器，需考慮其壓力損失，可經過計算或估算，估算損失一般在100—300Pa之間。
Pressure is the second element in fan selection. Based on the given or calculated operating density, the operating pressure is converted into the pressure under the standard state of the fan. If a fan is equipped with an intake box or muffler, its pressure loss needs to be considered. After calculation or estimation, the estimated loss is generally between 100-300Pa.
流量是選型過程的第三要素，如系統要求氣體的質量流量，則需要將氣體質量流量換算為風機標準狀態下的容積流量。如系統要求氣體的容積流量，則風機標準狀態下的容積流量與工況下的容積流量相同。
Flow rate is the third element in the selection process. If the system requires a mass flow rate of gas, it is necessary to convert the gas mass flow rate to the volumetric flow rate under the standard state of the fan. If the system requires a volumetric flow rate of gas, the volumetric flow rate of the fan under standard conditions is the same as that under operating conditions.
接下來就是求風機的比轉數，因為比轉數計算是風機選型過程中的重要步驟，是判斷風機選用具體模型的主要依據。將換算到風機標準狀態下的性能參數和轉速代入比轉數的計算公式，根據不同的轉速可求出不同的比轉數，一階比轉數是單吸風機的依據；二階比轉數是雙吸風機的依據。
The next step is to calculate the specific speed of the fan, as the calculation of the specific speed is an important step in the fan selection process and the main basis for determining the specific model of the fan. Substitute the performance parameters and speed converted to the standard state of the fan into the calculation formula for specific speed, and calculate different specific speeds based on different speeds. The first order specific speed is the basis for a single suction fan; The second order specific speed is the basis for the double suction fan.