通風(fēng)管道內(nèi)風(fēng)速及風(fēng)量的測(cè)定事項(xiàng)

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(一)測(cè)定位置的選擇

（1） Selection of measurement position

濟(jì)南通風(fēng)管道內(nèi)風(fēng)速及風(fēng)量的測(cè)定，是通過測(cè)量壓力換算得到。測(cè)得管道中氣體的真實(shí)壓力值，除了正確使用測(cè)壓儀器外，合理選擇測(cè)量斷面、減少氣流擾動(dòng)對(duì)測(cè)量結(jié)果的影響很大。測(cè)量斷面應(yīng)盡量選擇在氣流平穩(wěn)的直管段上。

The measurement of wind speed and air volume in Jinan ventilation ducts is obtained through pressure conversion. To measure the true pressure value of gas in the pipeline, in addition to using pressure measuring instruments correctly, selecting a reasonable measurement section and reducing airflow disturbance have a significant impact on the measurement results. The measurement section should be selected as much as possible on a straight pipe section with smooth airflow.

測(cè)量斷面設(shè)在彎頭、三通等異形部件前面(相對(duì)氣流流動(dòng)方向)時(shí)，距這些部件的距離應(yīng)大于2倍管道直徑。當(dāng)測(cè)量斷面設(shè)在上述部件后面時(shí)，距這些部件的距離應(yīng)大于4～5倍管道直徑。

When the measuring section is set in front of irregular components such as elbows and tees (relative to the direction of airflow flow), the distance from these components should be greater than twice the pipe diameter. When the measuring section is set behind the above-mentioned components, the distance from these components should be greater than 4-5 times the pipe diameter.

當(dāng)測(cè)試現(xiàn)場(chǎng)難于滿足要求時(shí)，為減少誤差可適當(dāng)增加測(cè)點(diǎn)。但是，測(cè)量斷面位置距異形部件的小距離少是管道直徑的1.5倍。

When it is difficult to meet the requirements on the testing site, measurement points can be appropriately increased to reduce errors. However, the small distance between the measurement section position and the irregular component is at least 1.5 times the diameter of the pipeline.

測(cè)定動(dòng)壓時(shí)如發(fā)現(xiàn)任何一個(gè)測(cè)點(diǎn)出現(xiàn)零值或負(fù)值，表明氣流不穩(wěn)定，該斷面不宜作為測(cè)定斷面。如果氣流方向偏出風(fēng)管線15°以上，該斷面也不宜作測(cè)量斷面

If a zero or negative value is found at any measuring point during the measurement of dynamic pressure, it indicates that the airflow is unstable, and this section should not be used as the measurement section. If the airflow direction deviates more than 15 ° from the centerline of the air duct, this section should not be used as a measurement section

(檢查方法：畢托管端部正對(duì)氣流方向，慢慢擺動(dòng)畢托管，使動(dòng)壓值大，這時(shí)畢托管與風(fēng)管外壁垂線的夾角即為氣流方向與風(fēng)管線的偏離角)。

(Inspection method: The end of the pitot tube is facing the airflow direction, and slowly swing the pitot tube to increase the dynamic pressure value. At this time, the angle between the pitot tube and the vertical line of the outer wall of the air duct is the deviation angle between the airflow direction and the centerline of the air duct.).

選擇測(cè)量斷面，還應(yīng)考慮測(cè)定操作的方便和。

When selecting a measurement section, consideration should also be given to the convenience and safety of the measurement operation.

(二)測(cè)試孔和測(cè)定點(diǎn)

（2） Test holes and measuring points

由于速度分布的不均勻性，壓力分布也是不均勻的。因此，必須在同一斷面上多點(diǎn)測(cè)量，然后求出該斷面的平均值。

Due to the non-uniformity of velocity distribution, the pressure distribution is also non-uniform. Therefore, it is necessary to measure multiple points on the same cross-section and then calculate the average value of that cross-section.

圓形風(fēng)道

Circular duct

在同一斷面設(shè)置兩個(gè)彼此垂直的測(cè)孔，并將管道斷面分成一定數(shù)量的等面積同心環(huán)，對(duì)于圓形風(fēng)道，測(cè)點(diǎn)越多，測(cè)量精度越高。

Set two perpendicular measuring holes on the same section and divide the pipeline section into a certain number of equal area concentric rings. For circular air ducts, the more measuring points, the higher the measurement accuracy.

矩形風(fēng)道

Rectangular duct

可將風(fēng)道斷面劃分為若干等面積的小矩形，測(cè)點(diǎn)布置在每個(gè)小矩形的，小矩形每邊的長度為200mm左右，圓風(fēng)管測(cè)點(diǎn)與管壁距離系數(shù)(以管徑為基數(shù))。

The cross-section of the air duct can be divided into several small rectangles of equal area, with measuring points arranged at the center of each small rectangle. The length of each side of the small rectangle is about 200mm, and the distance coefficient between the measuring points of the circular air duct and the pipe wall (based on the pipe diameter).

通風(fēng)管道內(nèi)風(fēng)速及風(fēng)量的測(cè)定事項(xiàng)就講解到這里了，希望能夠給您好的幫助，更多事項(xiàng)就來我們網(wǎng)站http://m.hwzxw.net咨詢！

That's all for the measurement of wind speed and airflow inside the ventilation duct. We hope it can be of great help to you. For more information, please come to our website http://m.hwzxw.net consulting service