NaK (45%/55). which is an alloy of sodium and potassium. is used to cool fast neutron nuclear reactors. The NaK flows at a rate of
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- 6.1 Determine the heat transfer coefficient at the stagnation point and the average value of the heat transfer coefficient for a single 5-cm-OD, 60-cm-long tube in cross-flow. The temperature of the tube surface is , the velocity of the fluid flowing perpendicular to the tube axis is 6 m/s, and the temperature of the fluid is . Consider the following fluids: (a) air, (b) hydrogen, and (c) water.arrow_forwardQ2:A) Define the bulk temperature (Tn), and prove that : T₁, - 2 ur dr B) Ethylene glycol flows at 0.01 kg/s through a 3 mm diameter, thin walled_tube. The tube is coiled and submerged in a well-stirred water bath maintained at 25 °C. If the fluid enters the tube at 85 °C, what heat rate and tube length are required for the fluid to leave at 35 °C ? At 60 °C, μ = 0.00522 kg/m.s, k = 0.26 W/m.K, C, 2562 J/kg.K. -arrow_forwardThe fluid flows at a speed of 0.4 m/s through a horizontally placed smooth pipe with a diameter of 20 mm and a length of 24 m and heats an environment at a temperature of 87 oC. Considering that the pipe surface temperature remains constant, inside the pipe; a) In case of water flow,b) In case of engine oil leakage Calculate the heat transfer coefficient and friction factor in the in-pipe flow and compare and interpret the results.arrow_forward
- A constant heat flux q = 200 W / m2 is applied to a circular section pipe with a diameter D = 50 mm and a length L = 8 m, and water flows at a flow of 0.01 kg / s under the pipe. The entrance temperature of the water to the pipe is 29 oC. Which of the following is the average fluid temperature at the outlet of the pipe (x = L) with the fluid transmission at 30 oC? a. 39.21 oC b. 84,23 oC c. 66,59 oC D. 61.43 oC e. 83,28 oCarrow_forward1. A hollow tube is designed to be a heater with the ability to provide uniform surface heat flux of 2000 W/m2 to the water that flows in it. The water with a velocity of0.3 mis enters the tube at a temperature of 15 °C and leaves the tube at a temperature of 45 °C. The tube is 13 m long with a diameter of 5 mm. a. is the flow laminar or turbulent? b. Is the flow fully developed? Prove it with appropriate calculation. c. Calculate the heat transfer coefficient for water that flows inside the pipe. d. What is the temperature of the surface at the exit point of the tube?, e. Evaluate the heat transfer performance when the velocity of water increases to 3 m/s. Briefly discuss your answer. 2. The double pipe, parallel flow heat exchanger is to be used to cool oil using sea water. The oil enter the heat exchanger at 0.15 kg/s and at a temperature of 90 °C. Meanwhile, the sea water enters the heat exchanger at 0.3 kg/sand at a temperature of 10 °C. The area of the heat exchanger is 11. 5 m2…arrow_forwardA 10 m long thin-walled stainless steel tube of diameter 15 mm is used to sterilize pharmaceutical products by heating it from 25 °C to 85 °C. A uniform heat flux is maintained on the outer surface of the tube by an electric resistance heater wrapped around it. If the flow rate of the liquid is 0.15 m/s, find the required heat flux. Is the flow in the tube laminar or turbulent? Assuming the fluid exits the tube with a fully developed velocity and temperature profile, determine the tube surface temperature at the exit. Explain the reasoning for assuming that the flow is fully developed.arrow_forward
- Water at 27°C flows with a mean velocity of 1 m/s through a 1 km-long pipe of 0.25 m inside diameter. Answer the following: a. Is the flow hydrodynamically fully developed? Support your answer with calculations. b. Is the flow thermally fully developed? Support your answer with calculations. c. What is the pressure drop over the pipe length, if the pipe surface is smooth? (Ans: 0.289 Bar) d. What is the pump power requirement, if the pipe surface is smooth? (Ans: 1.42 kW)arrow_forwardA shell-and-tube heat exchanger is used to cool compressed liquid methanol from 176 °F to 104 °F. The methanol flows on the shell side of the exchanger. The coolant is water that rises in temperature from 50 °F to 86 °F and flows within the tubes at a rate of 68.9 kg s1. Finding the appropriate thermophysical data and applying the proper equations, you are required to do the following: (a) Calculate i) methanol mass flow rate in the exchanger, ii) methanol volumetric flowrate at the inlet of the exchanger. (b) i) For the counter-current flow of the fluids calculate the log temperature difference, ii) explain the purpose of calculating this difference, iii) explain, quantitatively, why is the counter-current flow in heat exchangers preferred to co-current flow. meanarrow_forwardWater flows inside the tube 45mm diameter and 3.5 meters long at a velocity 1m/s. Determine the heat transfer coefficient and the rate of heat transfer if the mean water temperature is 50 degree celsius and the tube wall is 70 degree celsius. kfor water is 0.68W/m degree celsius and the kinematic viscocity is 0.478x10^-6 m2/s and the Pr= 2.98. use the Dittus and Boelter equation to solve for Nu.arrow_forward
- A liquid metal flows at the rate of 4kg/s through a constant heat flux 6cm inner diameter tube in a nuclear reactor. The fluid at 200 oC is to be heated with the tube wall 40 oC above the fluid temperature. Determine the length of the tube required 25 oC rise in bulk fluid temperature. Using the following properties: ρ = 7700 kg/m3 , Y = 8*10-8 m2/s , Pr=0.011 , Cp= 130 J/kg.K , k=12W/mk. please can you solve it with keyboard,take your time heat transfer, J.P.Holman .arrow_forwardA DPHX is made of a 6-nom sch 40 commercial steel outer pipe and a 5-nomsch 40S stainless steel inner pipe. The fluid in the annular space is cyclohexanethat has a volumetric flow rate of 120 gpm and an average temperature of 60°F. The fluid in the inner tube is water at an average temperature of 180°F andflowing at 320 gpm. Cyclohexane is an organic liquid and the water can be assumed to be distilled water. The thermal conductivity of the stainless steelinner pipe is 9.5 Btu/h·ft·°F. Determine the following:a. Convective heat transfer coefficients in the inner pipe and the annulus (Btu/h·ft2·°F).b. Overall heat transfer coefficient for the case of a clean heat exchanger (Btu/h·ft2·°F).c. Overall heat transfer coefficient if fouling is considered (Btu/h·ft2·°F).arrow_forwardEngine oil flows at a rate of 0.95 kg/s through a tube of 119 mm inside diameter and is heated from 293 to 327 K by condensing steam at 373 K. For the described case answer the following:i. Identify the type of flow and explain briefly about the flow with suitable assumptions & sketches.ii. Determine the inside heat transfer coefficient and rate of heat transfer per meter length of pipe for the identified flow pattern.arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning