Determine the wall thickness in Problem 4.5.8 if the valve closes in 60 sec and the pipe walls are assumed to be rigid.
Problem 4.5.8
A 700-m-long, 2.0-m-diameter steel penstock conveys water from a reservoir to a turbine. The reservoir water surface is l 50 m above the turbine, and the flow rate is 77. 9 m3/sec. A gate valve is installed at the downstream end of the pipe. Determine the wall thickness to avoid damage to the pipeline if the gate valve is closed rapidly. Use this equation (PD = 2Te) to determine the allowable pressure the pipe can withstand based on hoop stress theory with T = 1.1 × 108 N/m2. Neglect longitudinal stresses and assume that the operational pressure is minimal compared to the maximum water hanuner pressure.