Elements Of Electromagnetics
7th Edition
ISBN: 9780190698614
Author: Sadiku, Matthew N. O.
Publisher: Oxford University Press
expand_more
expand_more
format_list_bulleted
Related questions
Question
It is proposed to cool oil in a counter-current, concentric tube heat
exchanger composed of a thin-walled inner tube of 0.02 m diameter
carrying oil and thin-walled, perfectly insulated outer tube of 0.05 m
diameter carrying water. The oil flow rate is 50.0 kg min-1 and it has to be
cooled from 90°C to 40°C using 60 kg min-1 water at 20°C.
Determine the length required for the heat exchanger. Comment on
the practicality of this length.
Transcribed Image Text:The physical properties of potatoes
Density, p
Specific heat capacity, cp
Thermal conductivity, k
1080 kg m-3,
3400 J kg-1 K1,
Large: 0.4 W m-1 K-1, Small: 1.25 W m-1 K-1
The physical properties of air at 20°C
Density, p
Specific heat capacity, cp
Viscosity, u
Thermal conductivity, k
Prandtl number, Pr
1.164 kg m-3
1007 J kg-1 K-1
1.84x10-5 Pa s
0.03 W m-1 K-1
0.72
The physical properties of water
Density, p
Specific heat capacity, cp
Viscosity, µ
Thermal conductivity, k
Prandtl number, Pr
1000 kg m3,
4200 J kg-1 K-1,
1.00x10-3 Pa s,
0.64 W m-1 K-1,
4.7
The physical properties of oil
Density, p
Specific heat capacity, cp
Viscosity, u
Thermal conductivity, k
Prandtl number, Pr
880 kg m3,
1900 J kg-1 K-1,
5.00x10-3 Pa s,
0.140 W m-1 K-1,
68
Heat transfer coefficient correlations
1. Nu = 0.023RE0.8 Pr0.4
2. Nu = 0.53 (GrPr)025
Re 2 10000
gB(Ts-Too)d³
1
and g = 9.8 m s², ß
T; = surface temperature, T, = bulk temperature, v =
where Gr
thermal expansion coefficient,
v2
T
kinematic viscosity
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by stepSolved in 2 steps with 2 images
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- Please only first attempt (or you will be downnvoted)arrow_forwardA highly engineered Ecto-Containment System Protection Grid produces about 8 kW of waste heat in thesystem. A less highly-engineered tubular cross-flow heatsink is designed to dissipate that heat. In this case, the heat sink is a single long pipe carrying anti-freeze through the unit. The pipe has an OD of 80mm and and ID of 16mm. Assume that there is no resistance between the anti-freeze and the OD of the pipe (infinite conduction). Convection is forced, with an airflow of 12 m/s air across it Pr,air = 0.72, density(p) = 1.2 kg/m3, u = 16.83x10−6 Pa − S, k = 0.025 W/mk). The outside air is at 25℃ while the antifreeze is at 180℃. a) Find the Reynold’s Number of flow over the Pipe b) Find the convection coefficient across the pipe c) How long must the pipe be to dissipate all 8kW?arrow_forwardPlease show all steps, not Ai generated, has been wrong before. I need to understand the process.arrow_forward
- Please don't use chatgptarrow_forwardIn a concentric-pipe heat exchanger, one of the fluids is a condensing vapour and theother is the coolant. Sketch the variation in fluid temperatures of two fluids as theyflow through the heat exchanger. Indicate clearly the inlet and outlet of the coolantand its direction of flow.arrow_forwardAn air conditioning system is to be designed for industrial process for hot and wet summer conditions. The out door air is at 30 °C DBT and 75% RH. The required conditions is to be 22 °C DBT and 70% RH. The amount of free air circulated is 200 cmm. The coil surface temperature is 14 °C and the required conditions are achieved by first cooling with dehumidification and then by heating. Find out: (a) the cooling capacity and BPF of cooling coil (b) the amount of water vapor removedarrow_forward
- A refrigerant 22 condenser has four water passes and a total of 60 copper tubes that are 14 mm ID and have 2 mm wall thickness. The conductivity of copper is 3 90 W/m • K. The outside of the tubes is finned so that the ratio of outside to inside area is 1.7. The cooling-water flow through the condenser tubes is 3.8 L/s (a) Calculate the water-side coefficient if the water is at an average temperature of 30°C, at which temperature k = 0.614 W/m • K, p = 996 kg/m3 , andµ= 0.000803 Pa• s (b) Using a mean condensing coefficient of 1420 W/m2 • K, calculate the overall heat-transfer coefficient based on the condensing area.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_forwardA counter-flow heat exchanger is used to cool water from 60°C to 20°C. The water flows at 0.2 m/s through the inner tube and the cooling fluid flows in the enclosure. The inner tube is 6-cm in diameter and 15-m in length. It is thin and made of copper. The flow rate of the cooling fluid is 1.2 kg/s and convection coefficient is 360 W/m².°C. The specific heat of the cooling fluid is 1600 J/kg. °C. The surface temperature of the inner tube can be approximated as almost isothermal. (a) What is the mass flow rate of water? 0.56 kg/s (b) What is the effectiveness of this heat exchanger? 0.285arrow_forward
- Hello Sir,Good Afternoon. I have a question in my homework related Heat Transfer lesson. The following below is my question. Please Advice. Thank Youarrow_forwardThe condenser of a large thermal power plant is a body-tube type heat exchanger consisting of a single body and 30000 pipes with two passes each. The pipes are thin-walled with an inner diameter of 25 mm, and steam condenses on the outer surfaces of the pipes with a convection coefficient of 11000 W / m2.K. The heat transfer required by the heat exchanger is 2000 MW, and it is provided by the flow of water through the pipes at a flow rate of 30000 kg / h. Water enters at 20 ° C, steam condenses at 50 ° C. Calculate the temperature of the cooling water leaving the condenser? Determine the required pipe length per pass? The properties of water at Tort = 300 K; Cp = 4180 j / kgK, μ = 855 × 10--6 Ns / m2, k = 0.613 W / mK, Pr = 5.83.arrow_forwardSaturated steam at 1 atm is condensed on the external surface of a copper tube withan outside diameter 16 mm and tube wall of thickness 0.5 mm. The tube is cooledinternally by water with a mass flow rate of 0.06 kg/s, which in turn is raised intemperature from 15 oC to 60 oC as it flows through the tube.Take the heat-transfer coefficient at the condensing side as 10.0 kW/m2K and theisobaric specific heat-capacity of water as 4180 J/kg K.i) Calculate the heat transfer rate to the cooling water. ii)arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University Press
Mechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSON
Thermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education 
Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEY
Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning
Engineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY