【正文】 2 mm), the cold fluid (cp=1 kJ/(kg K), flow rate 500 kg/h) passes through the pipe and the hot fluid goes through the annular. The inlet and outlet temperatures of cold fluid are 20 oC and 80 oC, and the inlet and outlet temperatures of hot fluid are 150 oC and 90 oC , respectively. The hi (heat transfer coefficient inside a pipe) is 700 W/(m2 oC)and overall heat transfer coefficient Uo (based on the outside surface of pipe) is 300W/(m2 oC), respectively. If the heat loss is ignored and the conductivity of pipe wall (steel) is taken as 45 W/(moC), find:(1) heat transfer coefficient outside the pipe ho?(2) the pipe length required for counter flow, in m?(3)what is the pipe length required if the heating medium changes to saturated vapor(140 oC) which condenses to saturated liquid a。==5471=℃ hence, m180。 ρ=958kg/m3。==(4) oC(5)to increase the velocity of fluid flowing through the pipe The saturated vapor at temperature of 100oC is condensed to saturated liquid on the surface of a single vertical pipe with length and diameter 38mm (outside).The temperature of pipe wall is 92oC. What is the quantity of condensed vapor per hour? If the pipe is placed horizontally, what is the quantity of condensed vapor per hour?Solution:From the appendix 6, we obtain the latent heat of the saturated vapor, The average temperature of the condensate film=(100+92)/2=96℃The properties of the saturated water at 96 oC are as follows: 181。 as the flow rate decreases to 1125 kg/hh180。=103Pas，cp=℃，k=℃，ρ= 850kg/m3 at average temperature of 50℃and average velocity of benzene flowing through the annular space of double tube is calculated as followSubstituting the variables into equation 1 gives. Air at 2 atm and 20oC flows through in the pipe of tubular exchanger at 60m179。176。= cp, conductivity k= W/(m oC), and heat capacity cp =1 kJ/(kgK).Solution:. Methyl alcohol flowing in the inner pipe of a doublepipe exchanger is cooled with water flowing in the jacket. The inner pipe is made from 25mm Schedule 40 steel pipe. The thermal conductivity of steel is 45 W/(mCCC, and that of the outer face is 176。176。176。=500V= l Filtration is carried out in a plate and frame filter press, with 20 frames m square and 50mm thick. At a constant pressure difference of , onequarter of the total filtrate per cycle is obtained for the first 300s. Filtration is continued at a constant pressure for a further 1800s, after which the frames are full. The total volume of filtrate per cycle is m3 and dismantling and refitting of the press takes 500sIt is decided to use a rotary drum filter, long and in diameter, in place of the filter press. Assuming that the resistance of the cloth is the same and that the filter cake is inpressible, calculate the speed of rotation of the drum which will result in the same overall rate of filtration as was obtained with the filter press. The filtration in the rotary filter is carried out at a constant pressure difference of 70kN/m2 and with 25% of the drum submergedSolution:Area of filtration: A=220=Δp=t1=300s, V1=1/4=t2t1=1800s, ΔV==or t2 =2100s, V2=Vm=Andcapacityfor the rotary drum filterArea of filtration: A=πdL==Operating pressure:Δp=70kN/m2And the drum submerged : φ=25%For rotary drum filter the filtration coefficient: keep Vm unchanged, K changes with changing in pressure differencethe capacity of rotary drum filter is equal to that of press filterSolving for n from the equation above by trial and errorn==(轉(zhuǎn)/min) A press filter of filtering surface was used to separate the suspension containing calcium carbonate, operating in constant pressure. The volume of filtrate collected was 103 m3 during the 50 s, volume of filtrate collected was 103 m3 during the 100 s. How much will the filtrate be obtained as filtering for 200 s?solution：filtering area A= m2。s/ m178。/h, the viscosity of the gas is 180。s/m2 so 1from the maximum permissible velocity of the air is 3m/s 2set B to be 3m, then from equation 1L=7mAnd H= A standard cyclone is to be used to separate the dust of density of 2300 kg/m179。 and viscosity 181。=103N settles（沉淀） freely in the 20℃ air, try to calculate the maximum diameter obeying Stocks’ law and the minimum diameter obeying Newton’s law.Solution: The gravity settling is followed Stocks’ law, so maximum diameter of particle settled can be calculated from Re that is set to 1, thenequation for the terminal velocitysolving for critical diameter Check up the appendixThe density of 20℃ air ρ= kg/m179。) which is parallel with the main pipe. The total length including the equivalent length of all form losses of the attachedpipe is 10m. A rotameter is installed in the branch pipe. When the reading of the rotameter is , try to calculate the flow rate in the main pipe and the total flow rate, respectively. The frictional coefficient of the main pipe and the attachedpipe is and , respectively.Solution： The variables of main pipe are denoted by a subscript1, and branch pipe by subscript 2. The friction loss for parallel pipelines is The energy loss in the branch pipe is In the equation input the data into equation c The energy loss in the main pipe is So The water discharge of main pipe is Total water discharge is A Venturimeter is used for measuring flow of water along a pipe. The diameter of the Venturi throat is two fifths the diameter of the pipe. The inlet and throat are connected by water filled tubes to a mercury Utube manometer. The velocity of flow along the pipe is found to be m/s, where R is the manometer reading in metres of mercury. Determine the loss of head between inlet and throat of the Venturi when R is . (Relative density of mercury is ).Figure for problem Solution:Writing mechanical energy balance