Im struggling and I have exam tomorrow! Help idk how to do it Question 3 - Section B:A counter-flow, shell and tube heat exchanger is installed for heating cold water using a hot oil.The water flows in the thin-walled inner tubes (a bundle of tubes) while the oil flows in the shell.Water enters the inner tubes at 22 °C and leaves the tubes at 45 °C, while the oil enters the shellat 85 °C and leaves the shell at 52 °C. The bundle of tubes has a total effective length of 28 m andthe inner diameter of each thin cylindrical tube is 40 mm. The specific heat capacity of the oil is2.58 kJ/kgK and the specific heat capacity of water is 4.2 kJ/kgK. Mass flow rate of the oil is1.6 kg/s. Assume that there is no fouling and that the heat transfer in the heat exchanger from thehot fluid to the cold fluid is 100% effective.Determine:(iv) Logarithmic Mean Temperature Difference for this heat exchanger.(v) mass flow rate of the water in the bundle of tubes.(vi) the overall heat transfer co-efficient (U-value) of the heat exchanger to achieve the specifiedtemperature differences. (Use the Logarithmic Mean Temperature Difference - LMTD- method).

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Answered: Question 3 - Section B: A counter-flow,…

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter10: Heat Exchangers

Section: Chapter Questions

Problem 10.36P

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Mot water is used to heat air in a double-pipe heat exchanger as shown in the following sketch. If the heat transfer coefficients on the water side and on the air side are 550W/m2Kand55W/m2K respectively, calculate the overall heat transfer coefficient based on the outer diameter. The heat exchanger pipe is 5-cm, schedule 40 steel (k=54W/mK) with water inside.
QUESTION 6 En. Karim recently bought a 2-shell passes and 12-tube passes type heat exchanger for his metal factory to reduce the hot oil (cp = 2200 J/kg.K) temperature. The hot oil enters the heat exchanger through the shell passes at 160 °C with a flow rate of 0,2 kg/s. The coolant fluid used to reduce the hot oil temperature is water (cp = 4180 J/kg.K). Water flows through the heat exchanger pipe at 18 °C and at flow rate of 0.1 kg/s. The tube inside the heat exchanger is made of 1.8 cm diameter copper tube and the length is 3 m. If the overall heat transfer coefficient is 340 W/m².K, evaluate and discuss your finding for the following parameters; i. The maximum rate of heat transfer, ii. The actual rate of heat transfer, iii. The outlet temperatures of the water, and iv. The outlet temperatures of the oil.
QUESTION 7 A local brand of water heater has offered a counterflow concentric tube heat exchanger, consisting of thin walled copper drains with a diameter D; = 50 mm. Waste water from the shower enters the heat exchanger at Thi= 38 °C while fresh water enters the room at Te,j= 10 °C. The waste water flows down the vertical drain wall in a thin, falling film and providing h, = 10 kW/m²·K. i. If the annular gap is d = 10 mm, the heat exchanger length is L = 1 m, and the water flow rate is m = 10 kg/min, determine the heat transfer rate and outlet temperature of the warmed fresh water. ii. If a helical spring is installed in an annular gap so the fresh water is forced to flow a spiral path from the inlet to the fresh water outlet, resulting in he = 9050 W/m²-K, determine the heat transfer rate and outlet temperature of the fresh water. iii. Based on the result from Q5(b), calculate the daily saving if 15,000 guests each take 10 minutes shower per day and cost of water heating is…
Question # 2 A counterflow, concentric tube heat exchanger is used to cool the lubricating oil for a large industrial gas turbine engine. The flow rate of cooling water through the inner tube (D, = 25 mm) is 0.2 kg/s, while the flow rate of oil through the outer annulus (D, = 45 mm) is 0.1 kg/s. The oil and water enter at temperatures of 100 and 30°C, respectively. How long must the tube be made if the outlet temperature of the oil is to be 60°C? Given h; =2250 W/m² . K, h,=38.8 W/m² . K, C,(oil)=2131 J/kg.K, and C,(Water)=4178 J/kg.K Hint: Th= 100°C in, = 0.1 kg/s Oil D, = D,= Tro= 60°C 25 mm 45 mm in̟ = 0.2 kg/s Water Te = 30°C (x),I
A counterflow, concentric tube heat exchanger is used to cool the lubricating oil for a large industrial gas turbine engine. The flow rate of cooling water through the inner tube (D; = 25 mm) is 0.2 kg/s, while the flow rate of oil through the outer annulus (D = 45 mm) is 0.1 kg/s. The oil and water enter at temperatures of 100 and 30°C, respectively. How long must the tube be made if the outlet temperature of the oil is to be 60°C?
Question B3. A concentric tube heat exchanger is used to cool lubricating oil for a large diesel engine. The inner tube is constructed of 2 mm wall thickness stainless steel, having thermal conductivity 16 W/m K. The flow rate of cooling water through the inner tube (radius = 30 mm) is 0.3 kg/s. The flow rate of oil through the tube (radius = 50 mm) is 0.15 kg/s. Assume fully developed flow, if the oil cooler is to be used to cool oil from 90°C to 50°C using water available at 283K. The overall heat transfer coefficient is 21.9 W/(m2K). Calculate the length of the tube required for parallel (co-current) flow, and the length of the tube required for counter-current flow. The average heat capacity for oil is 2.131 kJ/(kgK) and for the water 4.178 kJ/(kgK).
Question 2 En. Karim recently install a hot water system operates by a solar energy. The system consists of double pipe counter flow heat exchanger. Cold waters enters a tube at 22°C at a rate of 0.1 kg/s, while hot air enters the heat exchanger at 90°C at a rate of 0.3 kg/s. The specific heat for both cold water and hot air is cp = 4180 J/kg.K and c, = 1010 J/kg.K , respectively. The overall heat transfer coefficient based on the inner side of the tube is 80 W/m².K. The length of the tube is 12 m and the internal diameter of the tube is 1.2 cm. En. Karim assigned you do the complete analysis on this hot water system including to calculate the effectiveness of the heat exchanger. As an engineer, you have to determine: i. the heat capacity rates of both fluids, ii. the maximum rate of heat transfer (kW), iii. the effectiveness of the heat exchanger (NTU method), iv. the actual rate of heat transfer (kW), and v. the outlet temperatures of both cold water and hot air.
Xylene out of the storage tank at a temperature of 308 K will be heated to a temperature of 343 K. For this purpose, 4500 kg/hour n-Butanol is used which will experience a decrease in temperature from 358 K to 338 K. To exchange heat between the two fluids, it was decided to use 5 (five) double pipe heat exchangers arranged in series each with a length of 6 m. The pipe diameters in the heat exchangers are 78 mm and 53 mm. Can you determine the fouling factor of the heat exchanger and the pressure drop that occurs in the heat exchanger
3.34 A flow rate of 1.4 kg/s of water enters the tubes of a two-shell-pass, four-tube-pass heat exchanger at 7°C. A flow rate of 0.6 kg/s of liquid ammonia at 100°C is to be cooled to 30°C on the shell side; U = 573 W/m²K. (a) How large must the heat exchanger be? (b) How large must it be if, after some months, a fouling factor of 0.0015 m²K/W is expected to build up in the tubes but we still want to deliver ammonia at 30°C? (c) If we make it large enough to accommodate fouling, to what temperature will it cool the ammonia when it is new? (d) At what temperature does water leave the new, enlarged exchanger? [(d) TH₂0 = 49.9°C.]
The clean U for an exchanger is 770 BTU/(hr 0 F ft2). Its tube area is 550 ft2. After operating for several months, it is heating water from 40 0F to 150 0F at a flow rate of 200 GPM with a heating fluid on the shell entering at 300 0F and exiting at 170 0 F. Has the overall U decreased significantly? how many 1.0 inch diameter, 20 ft long tubes would it take to equal the 550 ft2 area?
3.21 You must cool 78 kg/min of a 60%-by-mass mixture of glycerin in wa- ter from 108°C to 50°C using cooling water available at 7°C. Design a one-shell-pass, two-tube-pass heat exchanger if U = 637 W/m²K. Which side should the water flow through? Explain any design decision you make and report the area, TH₂0out and any other relevant features.
Shown below is a heat exchanger used to cool down the liquid in the tube. The shell is well insulated. (1) If the tube is selected as the system, select the correct energy balance equation._____________ A. B. C. D.

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