Duct wind resistance calculation

Duct wind resistance calculation
1.0, determine the air volume: (according to the studio for required airflow 15 cubic meters per hour per square meter) 100 x 15 = 1500 (m3 / h

2.0 air flow rate, calculate the pipe: v = Q / 3600 (ab)

= 1500 / (3600 * 0.15 * 0.45)

= 6.17 (m/s)

3.0, the calculation of wind pressure:

3.1, in order to calculate conveniently, rectangular duct conversion into a circular duct: ab/D = 2) 3.14 0.15 x 2 x) = 0.45/3.14 = 0.293 (m)

3.2, calculated pipeline along the frictional resistance:

1, lambda = 0.0011 / D = 0.0125 + 0.0125 + 0.0011/0.293 = 0.01625

2, R = (lambda/D) * (argument ^ 2 * gamma / 2) gamma air density of 1.2 kg/m after

= (0.01625/0.293) * (1.2/2) ^ 2 * 6.17 = 1.267 (Pa)

3, H = RL = 0.1267 x 70 = 886.9 (Pa)

4.0, elbow wind resistance calculation: (don't know elbow can not accurately calculate the bending radius) elbow making, turning radius as far as possible big, so can reduce the wind resistance bend, can approximate to wind resistance per meter of pipe. H = 7 * 6.17 = 43.19 (Pa)

5.0, the total resistance is: 886.9 + 43.19 = 930 (Pa)