郑州通风管道河南加工厂

这些风管选型知识你掌握了吗？
Do you have knowledge of these duct selection?
1、风管内的风速
1. Wind speed in the duct
一般空调房间对空调系统的限定的噪音允许值控制在40～50dB（A）之间，即相应NR（或NC）数为35～45dB（A）。根据设计规范，满足这一范围内噪音允许值的主管风速为4～7m/s，支管风速为2～3m/s。通风机与消声装置之间的风管，其风速可采用8～10m/s。
The noise allowable value of air conditioning system in general air conditioning room is controlled between 40 and 50 dB (A), that is, the corresponding NR (or NC) is 35 to 45 dB (A). According to the design specifications, the main wind speed is 4-7 m/s and the branch wind speed is 2-3 m/s to meet the noise allowable value in this range. The wind speed between fan and silencer can be 8 to 10m/s.
2、出风口尺寸的计算
2. Calculation of outlet size
为防止风口噪音，送风口的出风风速宜采用2～5m/s。风口的尺寸计算与风管道尺寸的计算基本相同，一般当层高在3~4米的房间大约取风速在2~2.5米每秒。根据经验一般可将使每个风口在20~25平方米的面积，其风量大约在500立方米左右。
In order to prevent the noise of the outlet, the outlet air velocity of the outlet should be 2 ~ 5m/s. The calculation of the tuyere size is basically the same as the calculation of the duct size. Generally, when the floor is 3-4 meters high, the wind speed is about 2-2.5 meters per second. According to experience, it is generally possible to make each tuyere in the area of 20-25 square meters, and its air volume is about 500 cubic meters.
3、回风口的吸风速度
3. Suction speed of return air inlet.
回风口位于房间上部时，吸风速度取4～5m/s，回风口位于房间下部时，若不靠近人员经常停留的地点，取3～4m/s ，若靠近人员经常停留的地点，取1.5～2m/s ，若用于走廊回风时，取1～1.5m/s 。
When the return air inlet is located at the upper part of the room, the suction speed should be 4-5m/s. When the return air inlet is located at the lower part of the room, if it is not close to the place where people often stay, it should be 3-4m/s. If it is close to the place where people often stay, it should be 1.5-2m/s. If it is used in the corridor, it should be 1-1.5m/s.
4、风管安装注意事项及风管计算
4. Precautions for air duct installation and calculation of duct
 在风管设计尽量小的情况下保证主管风速5m/s，支管风速3m/s，
Under the condition that the duct design is as small as possible, ensure that the wind speed is 5m/s and the branch wind speed is 3m/s.
 风管计算公式：所选设备风量÷3600÷风速=风管截面积
Calculation formula of air duct: selected equipment air volume, 3600 / wind speed = wind tunnel cross section area.
 同时注意保证风管：长边÷短边≤4 一般不要＞4 特殊情况特殊对待。
At the same time, we should also pay attention to ensure that the wind pipes are long, short, short, or less than 4, usually not 4.
 风口的选择：所选房间风量÷3600÷风速=散流器喉部截面积
Selection of air inlet: selected room air volume, 3600 wind speed = throat area of diffuser
 注意:双百叶风口截面积为以上公式所得面积÷0.7
Note: the area of the cross section of the double leaf blade is 0.7.
5、计算风管尺寸
5. Calculate the size of the duct.
1)等阻尼法(等压法)是一种方便的计算法，适用于多种场合。
1) equal damping method (isobaric method) is a convenient calculation method, suitable for many occasions.
2)根据下表确定主风管中的基本阻尼系数。
2) determine the basic damping coefficient of the main duct according to the following table.
风管类型
Type of wind pipe
阻尼系数（mmH2o)
Damping coefficient (mmH2o)
送风管
Air supply pipe
0.05-0.2
0.05-0.2
回风管
return duct
0.03-0.12
0.03-0.12
因回风管位于吸风部位，主要承受外部压力，应注意减轻其风管负担。对于风管系统，常采用送风管0.08-0.15mmH2O/m，回风管0.06-0.1 mmH2O/m作为基准。
Since the return air pipe is located at the suction part, it mainly bears external pressure. For the air duct system, the air supply pipe 0.08-0.15mmH2O/m and the return air pipe 0.06-0.1 mmH2O/m are often used as the benchmark.
6、在进行风管机的风管道设计时，注意在风管机的进、出风处加静压箱，以均衡风压，减少噪音，并且使静压箱内的流速保证在3米每秒以下，其长度可根据实际情况来定。
6. When designing the air duct of the air duct, pay attention to adding static pressure box at the inlet and outlet of the air duct to balance the air pressure and reduce the noise, and ensure the flow speed in the static pressure box below 3 meters per second, the length can be determined according to the actual situation.
7、风压估算
7. Wind pressure estimation
 如弯头、三通、变径等较少的情况下每米损失4pa左右。
Such as elbows, three links, variable diameter and so on less than 4pa loss per meter.
 如弯头、三通、变径等较多的情况下每米损失6pa左右。
Such as elbows, three links and variable diameters, the loss is about 6pa per meter.
管道式布风口是集风口、送风管道、静压箱、保温材料、风阀等功能为一体的中央空调末端送风系统。
Pipeline air distribution outlet is a central air conditioning terminal air supply system which integrates the functions of air outlet, air supply pipeline, static pressure box, insulation material, air valve and so on.
管道式布风口在沿管长方向上还有由于摩擦阻力和局部阻力造成的压力损失。因为压力损失与风速成正比关系，当气流沿管长方向风速越来越小时，阻力损失也不断下降。与此同时，风管个标准件以及出风口也存在局部阻力损失。管道式布风口送风系统以直管为主，系统中三通、弯头及变径很少，一般以沿程阻力损失为主，空气横断面形状不变的管道内流动时的沿程摩擦阻力按下式计算：
There is also pressure loss caused by friction and local resistance along the length direction of pipe. Because the pressure loss is proportional to the wind speed, the drag loss decreases as the wind speed decreases along the length of the pipe. At the same time, there are local resistance losses in the standard parts and outlet of the duct. The air supply system with ducted air distributor is mainly straight pipe, and the three-way, elbow and diameter change are very few in the system. In general, the friction loss along the pipeline is mainly caused by the loss of resistance along the pipeline, and the friction resistance along the pipeline is calculated according to the following formula.
——摩擦阻力系数；
- friction coefficient;
——风管内空气的平均流速，m/s；
The average velocity of air in the duct is m/s;
——空气的密度，kg/m3；
- air density, kg/m3;
——风管长度，m；
- length of air duct, m;
——圆形风管直径（内径），m；
- diameter of the round duct (inner diameter), m;
摩擦阻力系数 是一个不定值，它与空气在风管内的流动状态和风管管壁的粗糙度有关。
Friction resistance coefficient is an indefinite value, which is related to the flow state of air in the duct and the roughness of the duct wall.
根据对纤维材料和管道式布风口的综合性研究得到摩擦阻力系数 不大于0.024（铁皮风管大约0.019），由于管道式布风口延长度方向上都有送风孔，管内平均风速就是风管入口速度的1/2。由此可见 ，管道式布风口的延程损失比传统铁皮风管要小的多。
According to the comprehensive study of fiber material and ducted air distribution, the friction coefficient is less than 0.024 (about 0.019) and the average air velocity is 1/2 of the inlet velocity of ducted air distribution because there are air supply holes in the direction of elongation of ducted air distribution. It can be seen that the delay loss of the pipe type air outlet is much smaller than that of the traditional iron pipe.
部件局部压损计算
Partial pressure loss calculation of components
当管道式布风口内气流通过弯头、变径、三通等等部件时，断面或流向发生了变化，同传统风管一样会产生相应的局部压力损失：
When the air flow through the elbow, diameter change, tee and other components in the ducted air distribution outlet, the cross-section or flow direction changes, and the corresponding local pressure loss will occur as the traditional air duct:
Z：局部压力损失（pa）
Z: partial pressure loss (PA)
ξ：局部阻力系数（主要由试验测得，同传统风管中类似）
Zeta: partial resistance coefficient (mainly measured by test, similar to the same duct).
ρ：空气密度（kg/m3）
Rho: air density (kg/m3)
v：风速（m/s）
V: wind speed (m/s)
为了减少管道式布风口的局部损失，我们通常进行一定的优化设计：
In order to reduce the local loss of pipe type air distributor, we usually do some optimization design.
1． 综合多种因素选择管经，尽量降低管道内风速。
1. select various factors to control the wind speed.
2． 优化异形部件设计，避免流向改变过急、断面变化过快。
2. optimize the design of special-shaped parts, avoid changing the flow direction too quickly and changing the cross section too quickly.
根据实际工程经验，我们总结出各种管道式布风口部件的局部阻力值（风速＝8m/s），如下表：
Based on practical engineering experience, we summarize the local resistance values (wind speed = 8m / s) of various ducted tuyere components, as follows:
例如：某超市压损计算说明
For example: a supermarket pressure loss calculation description
对于该超市，AHU 空调箱风量为36000CMH，选取编号AHU-14号空调箱系统，主管尺寸为2000*610mm，共有5支支管，支管管径为559mm。选取最长不利环路25米主管+20.6米支管作为计算依据；
For the supermarket, the AHU air conditioning box air volume is 36 000 CMH, choose the number AHU-14 air conditioning box system, the main size of 2000*610 mm, a total of five branches, branch pipe diameter of 559 mm. The longest +20.6 meter branch pipe with a maximum length of 25 meters is chosen as the basis for calculation.
沿程阻力损失计算：
Resistance loss calculation along the line:
主管：25米， 2000*610mm，当量直径 ，
Supervisor: 25 meters, 2000*610mm, equivalent diameter.
支管道：20.6米， 559mm，，
Branch pipe: 20.6 meters, 559mm,
局部阻力损失计算：
Local resistance loss calculation:
等径三通局部损失为12Pa，对于变径三通取20Pa.
The local loss of equal diameter three passes is 12Pa, and 20Pa. for variable diameter three passes.
最长不利环路压损为20+8.5+6=34
The longest adverse loop pressure loss is 20+8.5+6=34