Pressure Spike

TWO-PHASE FLUID FLOW Fluid Flow where: DP = Pressure spike^� � � � � � lbf ft² r = Density of the fluid^� � � � � � lbm ft³ c = Velocity of the pressure wave � � � � � � ft sec (Speed of sound in the fluid) Dv = Change in velocity of the fluid^� � � � � � ft sec g_c = Gravitational constant 32.17^� � � � � � lbm ft lbf sec² Example: Pressure spike Water at a density of 62.4 lbm/ft³ and a pressure of 120 psi is flowing through a pipe at 10 ft/sec. The speed of sound in the water is 4780 ft/sec. A check valve suddenly closed. What is the maximum pressure of the fluid in psi? Solution: P_Max = P_Static + DP_Spike P_Max = 120^lbf in² rc DV g_c P_Max = 120^lbf in² 62.4^lbm ft³ 4780^ft sec 10^ft sec 32.17 lbm ft lbf sec² P_Max = 120^lbf in² 92,631^lbf ft² � � � � � � � � ft² 144 in² P_Max = 120^lbf in² 643.3^lbf in² P_Max = 763.3 psi HT-03 Page 44 Rev. 0