孔口與排氣量對照表

孔口與排氣量對照表

經過孔口之排氣,在 14.7psia ( 1 kgf / cm2 a ) 與 70 °F ( 21 °C )之大氣壓下每分鐘自由空氣之 M3

Dclivcry via Aperture, Free air M3 / min at 14.7 psia ( 1 kgf / cm2 a ) and 70 °F ( 21 °C )

孔口前錶壓力
Gauge pressure before passing through
孔口 直徑
Aperture d110iameter   ( mm )
0.397 0.794 1.588 3.175 6.35 9.525 12.700 15.875 19.050 22.225 25.400
kg / cm2 psi 排氣每分鐘之自由空氣
Free air delivery   e/min
排氣每分鐘 M3 之自由空氣
Free air delivery   m3 / min
0.068 1 0.793 3.172 12.744 50.976 0.203 0.459 0.813 1.274 1.832 2.495 3.257
0.136 2 1.133 4.475 17.927 71.650 0.286 0.646 1.147 1.793 2.583 3.512 4.588
0.211 3 1.360 5.494 21.948 87.792 0.351 0.787 1.402 2.195 3.144 4.305 5.607
0.272 4 1.586 6.315 25.261 100.819 0.405 0.909 1.614 2.526 3.625 4.956 6.460
0.340 5 1.756 7.023 26.423 112.430 0.450 1.011 1.798 2.812 4.050 5.522 7.193
0.408 6 1.926 7.703 30.867 122.909 0.493 1.107 1.968 3.087 4.418 6.032 7.873
0.476 7 2.067 8.298 33.134 132.538 0.530 1.195 2.124 3.313 4.758 6.514 8.496
0.612 9 2.351 9.374 37.382 150.096 0.598 1.351 2.399 3.738 5.409 7.363 9.600
0.816 12 2.960 10.733 43.046 171.902 0.688 1.546 2.749 4.305 6.174 8.411 10.988
1.020 15 2.974 11.894 47.578 190.310 0.762 1.713 3.059 4.758 6.853 9.317 12.178
1.360 20 3.483 13.905 55.507 222.595 0.889 2.002 3.568 5.551 8.015 10.903 14.245
1.701 25 3.965 15.916 63.720 254.314 1.017 2.291 4.078 6.372 9.147 12.461 16.284
2.041 30 4.475 17.927 71.650 286.032 1.147 2.580 4.588 7.165 10.337 14.047 18.351
2.381 35 4.984 19.909 79.579 320.016 1.274 2.860 5.098 7.958 11.470 15.604 20.390
2.721 40 5.494 21.920 87.792 351.168 1.405 3.712 5.607 8.780 12.631 17.190 22.458
3.061 45 5.975 23.930 95.722 382.320 1.532 3.455 6.117 9.572 13.792 18.748 24.497
3.401 50 6.485 25.941 103.65 416.304 1.660 3.738 6.655 10.365 14.953 20.334 26.564
4.082 60 7.476 30.019 119.794 478.608 1.914 4.305 7.675 11.979 17.247 23.449 30.642
4.762 70 8.496 33.984 135.653 543.744 2.172 4.899 8.694 13.565 19.541 26.597 34.749
5.442 80 9.487 37.949 151.795 606.048 2.427 5.466 9.714 15.180 21.835 29.736 38.827
6.122 90 10.478 41.914 167.654 671.184 2.685 6.032 10.733 16.765 24.160 32.800 42.933
6.803 100 11.498 45.878 183.797 736.32 2.945 6.627 11.753 18.380 26.451 36.023 47.040
7.483 110 12.489 49.843 199.656 798.624 3.200 7.193 12.801 19.966 28.773 39.167 51.146
8.163 120 13.480 54.091 215.798 863.76 3.455 7.760 13.820 21.580 31.067 42.310 55.252
8.503 125 13.990 56.074 223.728 894.912 3.568 8.043 14.300 22.373 32.228 43.868 57.291
  • 根據百分之百之流量係數,設若進口極圓時,則以 0.97 乘以值,設若為一銳緣孔口時,則乘數用 0.65。
  • 此表僅能產生近似之結果,若欲作精確之測量,則請見 ASME 動力試驗規格流動容積速度之測量。
  • 1 至 15psig 壓力值之計算,係使用標準絕熱公式。
  • 超過 15psig 壓力值計算,係使用此近似之公式: w=0.5303acp./( √ T )。其中 w= 每秒排出之磅數,a= 孔口面積,平方吋,c= 流量係數,p= 上流總壓力,psia,T= 上流溫度,F 絕對。
  • 上述情況值之計算係 c+1.0 , p= 錶壓 +14.7psia , T= 530F 絕對。
  • 重量數改為容量時,則使用每立呎 0.0749 磅密度因素,此係用於 14.7psia 則此 70F 乾空氣之修正。
  • 此公式不能用於 p ,少於兩倍大氣壓。
  • On thc basis of a 100% flow coefficient, supposc that the inlet is extremely round, then multiply the value by 0.97; if the aperture has knife edge, multiply them by 0.65.
  • We can obtain only approximate results here. Fore accurate mcasurement, refer to measurement of flow volume speed in ASME Power Experiment Specifications.
  • The standard thermal insulation formula is used in computation of pressure values between 1 and 15 psig.
  • For the computation of pressure values over 15 psig, the following approximate formula is used : w= 0.5303acp./( √ T ),in which w= delivered pounds/sec, a= aperture area( in2 ), c= flow coefficient, p= upstream gross pressure (psia), T= upstream temperature ( °F absolute).
  • In the above cases of computation, c= 1.0, p= gauge pressure +14.7 psia, T= 530°F absolute.
  • When weight is subtituted by volume, the density factor of 0.0749 lb / ft 3 is used instead, which is for 14.7 psia. So the 70°F is dry air correction.
  • Thc formula is not applicabie for p less than twice the atmospheric pressure.
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