Concept explainers
A concentric tube heat exchanger for cooling lubricating oil is comprised of a thin-walled inner tube of25-mm diameter carrying water and an outer tube of45-mm diameter carrying the oil. The exchangeroperates in counterflow with an overall heat transfercoefficient of
(a) If the outlet temperature of the oil is
(b) Determine the length required for the heatexchanger.
Want to see the full answer?
Check out a sample textbook solutionChapter 11 Solutions
Fundamentals of Heat and Mass Transfer
Additional Engineering Textbook Solutions
Foundations of Materials Science and Engineering
Statics and Mechanics of Materials (5th Edition)
DeGarmo's Materials and Processes in Manufacturing
Automotive Technology: Principles, Diagnosis, And Service (6th Edition) (halderman Automotive Series)
Thermodynamics: An Engineering Approach
Fluid Mechanics: Fundamentals and Applications
- Water stream (density 997 kg/m3) is fed to the shell side of a shell and tube heat exchanger in a mass flow rate of 561.9 t/h. The inner diameterof the shell is 45 cm, it contains 70 tubes of diameter 25/30 mm.Give the linear velocity at the shell side in m/s.arrow_forwardA double-pipe parallel-flow heat exchanger is used to heat water (cp = 4180 J/kg·K) from 25°C to 60°C at a rate of 0.2 kg/s. The heating is accomplished by geothermal water (cp = 4310 J/kg·K) available at 134°C at a mass flow rate of 0.3 kg/s. The inner tube is thin-walled and has a diameter of 0.8 cm. If the overall heat transfer coefficient of the heat exchanger is 550 W/m2·K, determine the length of the tube required to achieve the desired heating. (Round the answer to a single decimal place.) The length of the tube required to achieve the desired heating is ________ m.arrow_forwardA heat exchanger contains 400 tubes with inner diameter of 23 mm and outer diameter of 25 mm. The length of each tube is 3.7 m. The corrected log mean temperature difference is 23°C, while the inner surface convection heat transfer coefficient is 3410 W/m2·K and the outer surface convection heat transfer coefficient is 6820 W/m2·K. If the thermal resistance of the tubes is negligible, determine the heat transfer rate.arrow_forward
- Consider two double-pipe counter-flow heat exchangers that are identical except that one is twice as long as the other one. Which heat exchanger is more likely to have a higher effectiveness?arrow_forward2- In a heat exchanger, steam of 0.08 bar and a specific steam content of 95% is condensed. 381.6 tons / h cooling water with a temperature of 10 ̊C flows in parallel connected tubers with inner / outer diameter 28/30 mm with a speed of 0.65 m / s. The heat transfer surface of the heat exchanger is 220 m2 and it has a k-value of 2200 W / (m2K) . Assume the specific heat capacity of the water 4.18 kJ / (kg K) and density 1000 kg / m3. The K-value is attributed to the outer mantle surface of the tubes. a) Calculate the outlet temperature of cooling water. b) How many tonnes of steam per hour are condensed? c) Determine the number of tubes and tube lengtharrow_forwardThe mass flow rate, specific heat, and inlet temperature of the tube-side stream in a double-pipe, parallel-flow heat exchanger are 2700 kg/h, 2.0 kJ/kg·K, and 120°C, respectively. The mass flow rate, specific heat, and inlet temperature of the other stream are 1800 kg/h, 4.2 kJ/kg·K, and 20°C, respectively. The heat transfer area and overall heat transfer coefficient are 0.50 m2 and 2.0 kW/m2·K, respectively. Find the outlet temperatures of both streams in steady operation using (a) the LMTD method and (b) the effectiveness–NTU method.arrow_forward
- A double tube heat exchanger is made of copper (k = 380 W / m. ° C). Inner diameter of inner tube Di = 1.2 cm, outerits diameter is D0 = 1.6 cm and the diameter of the outer pipe is 3.0 cm. Convection heat transfer coefficient on the inner surface of the pipehigh = 700 W / m2. ° C and the heat transfer coefficient on the outer surface h0 = 1400 W / m2. ° C. Pipe sidecontamination factor Rf, i = 0.0005 m2. ° C / W and fouling factor Rf on the body side, 0 = 0.0002 m2. ° C / WAccording to the example; Calculate the thermal resistance of the heat exchanger per unit length.arrow_forwardA double tube heat exchanger is made of copper (k = 380 W / m. ° C). Inner diameter of inner tube Di = 1.2 cm, outerits diameter is D0 = 1.6 cm and the diameter of the outer pipe is 3.0 cm. Convection heat transfer coefficient on the inner surface of the pipehigh = 700 W / m2. ° C and the heat transfer coefficient on the outer surface h0 = 1400 W / m2. ° C. Pipe sidecontamination factor Rf, i = 0.0005 m2. ° C / W and fouling factor Rf on the body side, 0 = 0.0002 m2. ° C / WAccording to the example; Total heat transfer coefficients (U0 and Ui), taking into account the inner and outer surface areas of the pipecalculate.arrow_forwardIn a heat exchanger, a fluid with a density of 2.5 m per hour and a specific heat of 0.727 kcal / kg ° C cools from 120 ° C to 40 ° C and heats 10 m per hour with an inlet temperature of 10 ° C. Since the total heat transfer coefficient is 1000 kcal / m h ° C, (Psu-1000 kg / m²; Cpsu = 1 kcal / kg ° C) a) Parallel flow case, b) Counter flow case, calculate the surface area of the pipe.arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning