Consider electronic components mounted on the inner surface of a cylindrical tube. The components are cooled...
Fantastic news! We've Found the answer you've been seeking!
Question:
Transcribed Image Text:
Consider electronic components mounted on the inner surface of a cylindrical tube. The components are cooled by air flowing through the hollow center of the tube, as well as by convection between the outer surface of the tube and the surrounding air. The air at the tube inlet is at 27°C and 100 kPa, and the volumetric flow rate at the inlet is 0.0094 m³/s. When the air exits the tube, its temperature has increased to 42°C and its pressure is effectively the same as the inlet pressure. The so-called "thermal conductance" between the outside of the tube and the surrounding air, which is at 27°C, is hA = 4W/K, where h is the convection coefficient and A is the outer area of the tube. The electronic components consume power at a rate of 0.25 kW. a) If the inner diameter of the tube is 0.22 m, determine the average temperature of the outer surface of the tube. (Hint: how is the average temperature of the outer tube surface related to the rate of convection heat loss between the tube and the surrounding air?) b) Determine the rate of entropy production two ways: i. ii. By considering a control volume that only include the tube and its contents. By considering a control volume that extends beyond the outer tube wall to include the surroundings. c) Explain the difference between your results for parts (b-i) and (b-ii) above. Note that neither of these answers is "wrong", but that they do tell us different things. Consider electronic components mounted on the inner surface of a cylindrical tube. The components are cooled by air flowing through the hollow center of the tube, as well as by convection between the outer surface of the tube and the surrounding air. The air at the tube inlet is at 27°C and 100 kPa, and the volumetric flow rate at the inlet is 0.0094 m³/s. When the air exits the tube, its temperature has increased to 42°C and its pressure is effectively the same as the inlet pressure. The so-called "thermal conductance" between the outside of the tube and the surrounding air, which is at 27°C, is hA = 4W/K, where h is the convection coefficient and A is the outer area of the tube. The electronic components consume power at a rate of 0.25 kW. a) If the inner diameter of the tube is 0.22 m, determine the average temperature of the outer surface of the tube. (Hint: how is the average temperature of the outer tube surface related to the rate of convection heat loss between the tube and the surrounding air?) b) Determine the rate of entropy production two ways: i. ii. By considering a control volume that only include the tube and its contents. By considering a control volume that extends beyond the outer tube wall to include the surroundings. c) Explain the difference between your results for parts (b-i) and (b-ii) above. Note that neither of these answers is "wrong", but that they do tell us different things.
Expert Answer:
Answer rating: 100% (QA)
a To determine the average temperature of the outer surface of the tube we can use the energy balance equation for the tube and its contents The rate of convection heat loss between the tube and the s... View the full answer
Related Book For
Fundamentals Of Momentum Heat And Mass Transfer
ISBN: 9781118947463
6th Edition
Authors: James Welty, Gregory L. Rorrer, David G. Foster
Posted Date:
Students also viewed these mechanical engineering questions
-
A process is being developed to deposit a thin film of silicon electronic grade silicon (Si) onto the inner surface of a hollow glass optical fiber by thermal decomposition of silane (SiH 4 ) to...
-
Consider a 1.2-m-high and 2-m-wide glass window with a thickness of 6 mm, thermal conductivity k = 0.78 W/m·K, and emissivity ε = 0.9. The room and the walls that face the window...
-
An inductor has a linear change in current from 50 mA to 100 mA in 2 ms and induces a voltage of 160 mV. Calculate the value of the inductor.
-
Create an appropriate query that lists the first and last names of each employee and the person, if any, that employee reports to. (This is a case where the Employees table includes a primary key,...
-
Can you comment to these two posts of my classmates its discussion questions and i need to comment in two of them? To me, what makes someone beautiful changes in stages. My first initial perception...
-
Laffy Taffy is a type of taffy candy made from corn syrup, sugar, palm oil, and other ingredients. Laffy Taffy comes in a variety of flavors including strawberry, banana, and cherry. Suppose that...
-
Out Camping is a manufacturer of supplies and has several divisions, one of which is the tent division that produces that deluxe tent Away From Home. Fourteen thousand of these tents are made each...
-
QwikShare is a new not-for-profit organization that will rent low-emissions automobiles at QwikStops in suburban areas in order to provide an environmentally friendly transportation option to its...
-
The flowers in a garden at a resort need to be replaced. The choices for the flowers are Geraniums (G), Impatiens (I), Petunias (P), and Zinnias (Z). The head gardener holds an election in which all...
-
Mazie Supply Co. uses the percent of accounts receivable method. On December 31, it has outstanding accounts receivable of $66,500, and it estimates that 5% will be uncollectible. Prepare the...
-
( a ) Which two ( out of the three ) would be the best lead compounds? Why? ( b ) Describe the differences between the affinities and efficacies of the two compounds you selected in ( a ) . 4. 100%...
-
Thermopolis Industries acquired common stock of Riverton, Inc. as an investment. Consider the following transactions. 2018: Purchase 4,000 (15%) of the common shares of Riverton, Inc. for $20.40 cash...
-
Please help on my assignment. The main menu should look like this: Java Credit Main Menu [1] New Credit Account [2] Credit Inquiry [3] Purchases [4] Payment [5] Close Credit Account [7] Exit Below...
-
A company provides the following information related to its inventory. Inventory Number of Units Unit Cost Unit NRV Item A 3 , 8 0 0 $ 5 2 $ 4 6 Item B 4 , 2 0 0 2 8 3 0 Item C 2 , 5 0 0 3 4 3 1 Item...
-
Solve the question given below Product 101 102 103 104 Total Cost $ 124,000 92,800 61,800 31,000 The normal profit is 20% of total cost. Required 1 Required 2 Total Replacement Required: 1. Determine...
-
As discussed in class, if we make some simplifying assumptions (including that the density of air is that at sea level and angle of attack is 6), then wing loading, W/S = 0.38V2. (where W is weight,...
-
Graph the following conic sections, labeling vertices, foci, directrices, and asymptotes (if they exist). Give the eccentricity of the curve. Use a graphing utility to check your work. 10 5 + 2 cos 0
-
If the 7.5-cm-diameter hole in Problem 23.18 were drilled to a depth of 5 cm, what heat loss would result? Data From Problem 23.18 A 7.5-cm-diameter hole is drilled in a 10-cm-thick iron plate. If...
-
Consider a single, porous, spherical, inert mineral particle. The pores inside the particle are filled with liquid water (species B). We are interested in analyzing the molecular diffusion of the...
-
A small spherical bead is used as a controlled drug release capsule in the gastrointestinal system (i.e., your stomach). In this particular case, a 0.10-cm diameter bead has a uniform initial...
-
A stock price is governed by \[\frac{\mathrm{d} S}{S}=\mu \mathrm{d} t+\sigma \mathrm{d} z\] where \(z\) is a standardized Wiener process. Interest is constant at rate \(r\). An investor wishes to...
-
The current price of gold is \(\$ 412\) per ounce. The storage cost is \(\$ 2\) per ounce per year, payable quarterly in advance. Assuming a constant interest rate of \(9 \%\) compounded quarterly,...
-
At the beginning of April one year, the silver forward prices (in cents per troy ounce) were as follows: The carrying cost of silver is about 20 cents per ounce per year, paid at the beginning of...
Study smarter with the SolutionInn App