(20 Pts) A long steel pipe (Ksteel = 15 W m K-) transports water at T1...
Fantastic news! We've Found the answer you've been seeking!
Question:
Transcribed Image Text:
(20 Pts) A long steel pipe (Ksteel = 15 W m K-) transports water at T1 = 50C. The pipe has inner radius r = 10 mm and is 2 mm wall thickness. The heat transfer coefficient inside the pipe to the water is h = 25 W m K-. The pipe has two layers of insulation: a ceramic (Kc = 5 W m K-) layer 3 mm thick and a polymer (kpoly = 0.5 W m K-, &= 0.67) layer 6 mm thick. The outer polymer layer loses heat to the surroundings (ho = 12 W m K-, T%= 20C). A thin film strip heater is sandwiched between the ceramic and polymer layers to keep the water warm, and generates 100 W m. NOTE: the pipe's length is not indicated, you can either assume a unit length or explain that it is not necessary in your calculations of temperature. h = 25 W/mK Tj = 50C Strip heater Tsurr = 20C ho = 12 W/mK To = 20C 222 Steel pope my Ceramic A Polymer (5 Pts) Draw a resistance network to represent the heat transfer processes in this system. You can neglect any contact resistances between the solids. Label each resistance, important temperature nodes, and indicate the direction(s) of heat transfer in the network. (5 Pts) Neglecting radiation losses on the outer polymer surface, calculate each thermal resistance, and indicate what each resistance represents. Use your resistance network to calculate the heater's temperature and the polymer's outer surface temperature. (5 Pts) Calculate the percentage distribution of heat used to keep the water warm and the heat loss to the environment. (5 Pts) Recalculate parts (b) and (c), but this time include the outer surface radiation resistance. As you can see, the radiation resistance is a function of the unknown polymer's surface temperature; thus, this problem must be solved iteratively using any of the following methods. I would recommend using EES to solve the problem as is. Use the Update Guesses button to initialize the variable that represents the polymer's outer surface temperature as 293.15 K. You can solve this problem by hand. Start the solution process by assuming that the polymer's outer temperature is Tsum, followed by a calculation of the heat loss to the environment, and then using the heat loss to calculate the polymer's surface temperature. One more iteration of this process would yield the right answer. (20 Pts) A long steel pipe (Ksteel = 15 W m K-) transports water at T1 = 50C. The pipe has inner radius r = 10 mm and is 2 mm wall thickness. The heat transfer coefficient inside the pipe to the water is h = 25 W m K-. The pipe has two layers of insulation: a ceramic (Kc = 5 W m K-) layer 3 mm thick and a polymer (kpoly = 0.5 W m K-, &= 0.67) layer 6 mm thick. The outer polymer layer loses heat to the surroundings (ho = 12 W m K-, T%= 20C). A thin film strip heater is sandwiched between the ceramic and polymer layers to keep the water warm, and generates 100 W m. NOTE: the pipe's length is not indicated, you can either assume a unit length or explain that it is not necessary in your calculations of temperature. h = 25 W/mK Tj = 50C Strip heater Tsurr = 20C ho = 12 W/mK To = 20C 222 Steel pope my Ceramic A Polymer (5 Pts) Draw a resistance network to represent the heat transfer processes in this system. You can neglect any contact resistances between the solids. Label each resistance, important temperature nodes, and indicate the direction(s) of heat transfer in the network. (5 Pts) Neglecting radiation losses on the outer polymer surface, calculate each thermal resistance, and indicate what each resistance represents. Use your resistance network to calculate the heater's temperature and the polymer's outer surface temperature. (5 Pts) Calculate the percentage distribution of heat used to keep the water warm and the heat loss to the environment. (5 Pts) Recalculate parts (b) and (c), but this time include the outer surface radiation resistance. As you can see, the radiation resistance is a function of the unknown polymer's surface temperature; thus, this problem must be solved iteratively using any of the following methods. I would recommend using EES to solve the problem as is. Use the Update Guesses button to initialize the variable that represents the polymer's outer surface temperature as 293.15 K. You can solve this problem by hand. Start the solution process by assuming that the polymer's outer temperature is Tsum, followed by a calculation of the heat loss to the environment, and then using the heat loss to calculate the polymer's surface temperature. One more iteration of this process would yield the right answer.
Expert Answer:
Related Book For
Fundamentals of Thermal-Fluid Sciences
ISBN: 978-0078027680
5th edition
Authors: Yunus A. Cengel, Robert H. Turner, John M. Cimbala
Posted Date:
Students also viewed these mechanical engineering questions
-
Sam had the following sources of income for 2 0 2 2 Dividends $ 1 , 5 0 0 Salary $ 7 0 , 0 0 0 Interest $ 2 , 0 0 0 Net Rental income $ 5 , 0 0 0 bonus $ 1 0 , 0 0 0. What is sam's earned income for...
-
A three-phase line has an impedance of 1 + j3 per phase. The line feeds a balanced delta-connected load, which absorbs a total complex power of 12 + j5 k VA. If the line voltage at the load end has...
-
The Organization for Economic Co-operation and Development (OECD) website stats.oecd.org/index.aspx has a wealth of economic data. For example, under Monthly Economic Indicators, find International...
-
Find the largest clamping force that can be applied by the cast iron C-clamp if the allowable normal stresses on section m-n are 15 MPa in tension and 30 MPa in compression.
-
Explain how Bayes theorem can be used to develop learning systems.
-
Quality Watches completed the following selected transactions during 2012 and 2013: 2012 Dec 31 Estimated that uncollectible account expense for the year was 2% of credit sales of $450,000 and...
-
explain the neurobiological impact of chronic stress on the brain, and how this affects cognitive function and emotional regulation ?
-
The trial balance of Pacilio Security Services Inc. as of January 1, 2017, had the following normal balances: Cash ................. 78 , 972 P e t t y C a s h . . . . . . . . . . . . . . . . 100 A c...
-
Below data extracted from Dolly Trading for the year ending 30 June 2022. Dolly Trading Statement of Financial Position as at 30 June 2022 (RM) Land Shop lot Accumulated depreciation Cash Inventory...
-
When a company sells its accounts receivable, it is important to deduct the amount received on the sale from CFFO before comparing CFFO to operating income when looking for signals of overstatement...
-
Graph the lines in Problems 31-44. \(y=-0.01 x\)
-
To coax even more orders for sales, Sunbeam increasingly gave customers the right to return goods, yet Sunbeam did not increase the _________________ for _________________ in the its accounting...
-
If Xeroxs revenue recognition is delayed over the life of the contract, it could be a signal that the company is trying to shift its revenue to accelerate its recognition. True/False
-
Xerox had sold approximately $400 million of its accounts receivable in order to reduce the reported CFFO. True/False
-
In the Quality of GPS network what is the meaning that the normalized or standardized residuals have a value 1.0? Select one: a. The residuals are less than expected b. The residuals are large as...
-
A sample statistic will not change from sample to sample. Determine whether the statement is true or false. If it is false, rewrite it as a true statement.
-
Why are the convection and the radiation resistances at a surface in parallel instead of being in series?
-
The weight of a diesel engine is directly proportional to the compression ratio (W = kr) because extra metal must be used to strengthen the engine for the higher pressures. Examine the net specific...
-
Under what conditions can the overall heat transfer coefficient of a heat exchanger be determined from U = (1/h i + 1/h o ) -1 ?
-
With reference to Exercise 11.9, test the null hypothesis \(\beta=0.40\) against the alternative hypothesis \(\beta>\) 0.40 at the 0.05 level of significance. Data From Exercise 11.9 11.9 Scientists...
-
The level of pollution because of vehicular emissions in a city is not regulated. Measurements by the local government of the change in flow of vehicles and the change in the level of air pollution...
-
Give two reasons to explain why a company usually seeks to manage rather than eliminate its risks.
Study smarter with the SolutionInn App