Question

In the figure shown below two new cast iron pipes in series, D1 =0.8m, D2 =0.6m the first pipe of length of L1=400m, while the second of length of L2=350m, level at A =120m, Q = 0.1.5m3/s (T=25oC).there are a sudden contraction between Pipe 1 and 2, and Sharp entrance at pipe 1. Fine the total head of energy losses

Answer 1

$$A_1=\pi d^2=3.14\times(0.4)^2=0.5024m^2$$

$$A_2=\pi d^2=3.14\times(0.3)^2=0.2826m^2$$

$$V_1=A_1L_2=0.5024\times400=200.96m^3$$

$$V_2=A_2L_2=0.2826\times350=98.91m^3$$

Total heat of energy losses

$$Q_1=AV_1=120\times200.96=24.11J$$

$$Q_2=AV_2=120\times98.91=11.86J$$

$$∆Q=Q_1-Q_2=24.11-11.86=12.25J$$