16.In a laboratory, the acetic acid(70%)at 20C is sent by the glass pipe. The inside diameter of the pipe is 1.5m, and the flow rate is 10kg/min. Calculate Reynolds number in SI system and pectively. what is the flow solution: 1)In SI system (70%,p=1069kg/m3(20℃) 25×10-3N.s/ d=1.5cm=0.0151 0.882m/ 60×2×0.0152×1069 dp0.015×0882×1069 2.5×10-2 5657(belong to the overfall) 2) In physical unit system p=1.0698/cm3 =0.025gA(cm·s d=1 u=88.2cm/s 1.5×88.2×1.069 R =5657 0.025 17. The liquid whose density is 850kg/m,, viscosity is 8cp, flows in the steel pipe(inside diameter is 14mm). The velocity of liquid is Im/s. Try to find 1)The Reynolds number, and the flow pattern is pointed out 2) The position at which the local velocity is equal to the average one 3) Suppose the pipeline is horizontal pipe, and the pressure of the upstream is 1.5kgf/cm, How long the liquid has to flow when the pressure drop to 1. 3kgf/cm Solution: 1 )The Reynolds number R=如=00141×850=1480do 1000 2) The position at which the local velocity is equal to the average one16.In a laboratory, the acetic acid (70%) at 20℃ is sent by the glass pipe. The inside diameter of the pipe is 1.5m, and the flow rate is 10kg/min. Calculate Reynolds number in SI system and physical unit system, respectively. What is the flow pattern? solution：1）In SI system From appendix 17 of the book, for the acetic acid (70%), 3  = 1069kg / m (20℃)， 3 2 = 2.510 N s/ m −  d=1.5cm=0.015m u 0.882m /s 0.015 1069 4 60 10 2 =    =  2 2.5 10 0.015 0.882 1069 −    = =  du Re =5657 (belong to the overfall) 2）In physical unit system 5657 0.025 1.5 88.2 1.069 88.2 / 1.5 0.025 /( ) 1.069 / 3 =   = = = =  = Re u cm s d cm g cm s g cm   17. The liquid whose density is 850kg/m³, viscosity is 8cp, flows in the steel pipe (inside diameter is 14mm). The velocity of liquid is 1m/s. Try to find : 1) The Reynolds number, and the flow pattern is pointed out. 2) The position at which the local velocity is equal to the average one. 3) Suppose the pipeline is horizontal pipe, and the pressure of the upstream is 1.5kgf/cm², How long the liquid has to flow when the pressure drop to 1.3kgf/cm²? Solution：1）The Reynolds number 1488 1000 8 0.014 1 850 =   = =  du Re (belong to the overfall) 2）The position at which the local velocity is equal to the average one