风管计算三种方法:静压恢复法假定风速法等摩擦法空调风系统管道设计(一)在设计管机时首先要从产品数据中了解三个参数:风量、风压、噪声。1.风量:确定送风管道的尺寸。2.风压:又称外部静压。为了计算出克服送风过程中阻力所需要的参数。简单地说，或者不确切地说，风能吹多远。3.噪音:产品技术数据的噪音只是相对的，因为噪音随条件不同而变化。噪声可能由以下渠道产生:机器本身的风机、机器运行时的振动、送风压力过大等。(2)风道系统设计的主要内容包括: reasonable use of the air velocity in the pipe to determine the section size of the air duct, calculation of the resistance of the air system and selection of fans, balance the resistance of each branch of the air duct to ensure that the air volume of each branch of the air duct reaches the design value. So how to choose the wind speed in the pipe? How to determine the size of the air duct? ※ The selection of wind speed in the pipe determines the size of the section of the pipe. The relationship between the two is as follows: F=a×b=L/(3600• V) (Formula 1-1) in the formula: F: pipe section area (㎡) a, b: pipe section length, width (m) L: duct air volume (m³/h) V: wind speed (m/s) The above values are affected by the following aspects: ① building space: In modern buildings, whether multi-storey buildings or high-rise buildings, or high-grade villas, the building space is quite tight, so we are required to improve the wind speed as much as possible to reduce the section of the air duct. (The wind speed in the pipe is inversely proportional to the cross-sectional area of the air duct, that is, the higher the wind speed, the smaller the cross-sectional area of the air duct; on the contrary, the lower the wind speed, the larger the cross-sectional area of the air duct.) (2) Fan pressure and energy consumption: the higher the wind speed, the greater the wind resistance, the greater the energy consumption of the fan, and from this point on to reduce the wind speed. (3) Noise requirements: The influence of wind speed on noise is manifested in three aspects: First, with the increase of wind speed, the fan pressure requirement is higher, which causes the fan operation noise to increase; Second, when the wind speed increases to a certain extent, airflow noise will be generated when passing through the air duct components; Third, with the increase of wind speed, the noise reduction ability of the air duct. In general, the higher the wind speed in the duct, the greater the noise generated. Therefore, the selection of wind speed in the pipe is a result of comprehensive balance of various factors. Through access to relevant information and relevant manuals and according to the experience of the actual project.