EXAMPLE 6.1.2. HEAD LOSS USING DARCY WEISBACH FORMULA

What is the frictional loss of head for a 400m long pipe of 200mm diameter and carrying 50 liters per second of water?

                   

where:   L =  400m
             D = 200mm  0.20m


             

So velocity is computed as follows:

                 

Then, friction factor, f, can be computed by interpolation:

Pipe dia		Mean	Velocity	(V)	in Feet	per	Second
(in)	0.50	1.00	2.00	3.00	4.00	5.00	10.00	15.00	20.00
0.5	0.042	0.038	0.034	0.032	0.030	0.029	0.025	0.024	0.023
0.75	0.041	0.037	0.033	0.031	0.029	0.028	0.025	0.024	0.023
1	0.040	0.035	0.032	0.030	0.028	0.027	0.024	0.023	0.023
1.5	0.038	0.034	0.031	0.029	0.028	0.027	0.024	0.023	0.023
2	0.036	0.033	0.030	0.028	0.027	0.026	0.024	0.023	0.022
3	0.035	0.032	0.029	0.027	0.026	0.025	0.023	0.022	0.022
4	0.034	0.031	0.028	0.026	0.026	0.025	0.023	0.022	0.021
5	0.033	0.030	0.027	0.026	0.025	0.024	0.022	0.022	0.021
6	0.032	0.029	0.026	0.025	0.024	0.024	0.022	0.021	0.021
8	0.030	0.028	0.025	0.024	0.023	0.023	0.021	0.021	0.020
10	0.028	0.026	0.024	0.023	0.022	0.022	0.021	0.020	0.020
12	0.027	0.025	0.023	0.022	0.022	0.021	0.020	0.020	0.019
14	0.026	0.024	0.022	0.022	0.021	0.021	0.020	0.019	0.019
16	0.024	0.023	0.022	0.021	0.020	0.020	0.019	0.019	0.018
18	0.024	0.022	0.021	0.020	0.020	0.020	0.019	0.018	0.018
20	0.023	0.022	0.020	0.020	0.019	0.019	0.018	0.018	0.018
24	0.021	0.020	0.019	0.019	0.018	0.018	0.018	0.017	0.017
30	0.019	0.019	0.018	0.018	0.017	0.017	0.017	0.016	0.016
36	0.018	0.017	0.017	0.016	0.016	0.016	0.016	0.015	0.015
42	0.016	0.016	0.016	0.015	0.015	0.015	0.015	0.015	0.014
48	0.015	0.015	0.015	0.015	0.014	0.014	0.014	0.014	0.014
54	0.014	0.014	0.014	0.014	0.014	0.014	0.013	0.013	0.013
60	0.014	0.013	0.013	0.013	0.013	0.013	0.013	0.013	0.012
72	0.013	0.012	0.012	0.012	0.012	0.012	0.012	0.012	0.012
84	0.012	0.012	0.011	0.011	0.011	0.011	0.011	0.011	0.011

f= 0.026224

Thus, head loss is computed as follows:

RELATED TOPIC:

6.0. PIPES