What is the fin effectiveness of a rectangular plate fin made of aluminum O.3 mm thick mounted on a 16-mm-OD tube if the vertical tube spacing is 50 mm and the horizontal spacing is 40 mm? The air-side heat-transfer coefficient is 65 W/m2 • K, and the conductivity of aluminum is 202 W/m • K.
Q: What is the critical radius of insulation for a sphere equal to? k = thermal conductivity in W/m-K h…
A: Let k = Thermal conductivity and h = Heat transfer coefficient. Critical radius of insulation for…
Q: A spherical tank with internal diameter of 2 m made of 2.0-cm-thick stainless steel (k=15 W/m.K) is…
A: Note: As per our guidelines we are supposed to answer only the first 3 sub-parts. Kindly repost…
Q: A steam turbine casing is made of a 6mm thick steel plate. At one location it has an inside surface…
A: Given data: The thickness of steel, LS = 6 mm. Inside surface temperature, Ti = 100°C. Ambient…
Q: Calculate the effectiveness for a fin with a cross-sectional area of Ac=0.31, a base temperature…
A:
Q: A dormitory at a large university, built 50 years ago, has exterior walls constructed of…
A: Write the given values with suitable variables. Ls=25 mm=0.025 mks=0.1 W/m.KLi=25 mm=0.025 mki=0.029…
Q: A steel fin (k = 54 W/m-K) with a cross-section of an equilateral triangle, 5 mm in side is 80 mm…
A:
Q: A hot surface at 250°C is to be cooled by attaching straight aluminum rectangular fins (k = 240 W/m…
A: Given Data Thermal conductivity, K=240 W/mK Length of the fin, L=25mm The width of the fin, b=50mm…
Q: A thick-walled tube of stainless steel [ K=19 W/ m-ºC]. with 2-cm inner diameter (ID) and 4-cm outer…
A:
Q: Determine the temperature variation inside the iron plate with a thickness of 1.5 mm,…
A: Given, T∞ = 18 oC h = 11 W/m2K k = 21 W/mK A = 310 cm2 = 0.031 m2 l = 1.5 mm = 1.5 x 10-3 m Q = 2 kW…
Q: A thick-walled tube of stainless steel with thermal conductivity k = 19 W/m°C has inner diameter of…
A:
Q: Heat Trarnsier & Applications ISTe Q1. The heat flux through a wood slab 50 mm thick, whose inner…
A: We have to find thermal conductivity of wood
Q: A 50-meter-long cast iron pipe with a 10-centimeter outside diameter goes through a 288 K…
A:
Q: A food cold storage room is to be constructed of an inner layer of 19.1 mm of pine wood, a middle…
A:
Q: based on the information given here. Steam in a heating system flows through tubes whose outer…
A: Given Surface area, A = 0.001916 m2 Thermal conductivity, k = 186 W/ moC…
Q: A total of 10 rectangular aluminum fins (k =203 W/m·K) are placed on the outside flat surface of…
A: Given data as per question No. of fins = 10 Thermal conductivity of the fin = 203 w/m.k Width of fin…
Q: r surface of the wall is at 1100◦C, and the room temperature is 25◦C. The heat-transfer coefficient…
A: given:
Q: A steam pipe 100mm external diameter is to be lagged with two layers of different lagging material…
A:
Q: A cold storage room is constructed of an inner layer of 12.7 mm of pine, a middle layer of 101.6 mm…
A:
Q: 12. A 3.1 cm long straight rectangular fin has a thickness of 2.7 mm. The thermal conductivity is 52…
A: What is the fin efficiency? Fin efficiency is the ratio of actual heat dissipated by the fin to the…
Q: (2) Calculate the heat flux and overall heat transfer coefficient for two-layer wall, which consists…
A:
Q: A furnace wall comprises three layers of thickness 250 mm, 100 mm, and 150 mm with thermal…
A:
Q: A thick-walled tube of stainless steel [18% Cr, 8% Ni, k= 19 W/m - °C] with 2-cm inner diam- eter…
A:
Q: For your company you need to mass produce 20-cmx10-cm heat sinks to dissipate heat quickly from an…
A: Given data, Dimension of the base/sink = 0.2 m×0.1 m Convective heat transfer coefficient of the…
Q: Q2/ An insulated steam pipe having an outside Steam pipe diameter of 30 mm is to be covered with two…
A: Given Thermal conductivity(k1)=5k2 T1 and T2 are fixed Thickness = 20mm=0.02m Outside…
Q: A steam-carrying steel-pipe has inner and outer diameter of 85 mm and 110 mm, respectively. It is…
A:
Q: Water flows at 67 C inside a 2.5 cm inside diameter tube such that hi = 3500 W/m² .C. The tube has a…
A:
Q: Please answer: Calculate the correct rate of heat loss through the vertical walls of a boiler…
A: Given that, Dimension of furnace wall, l×b×h=4×3×3 m3Thermal conductivity of inner brick, kb=0.4…
Q: Explain and write legibly
A: It has been two choices to choose the fin. We have to decide which is suitable for quick heat…
Q: 4. The section of a vertical wall is made up of fiberglass insulation slabs separated by wooden…
A:
Q: Steam in a heating system flows through tubes whose outer diameter is 5 cm and whose walls are…
A: Given Data Outer diameter of tubes is : D1=5 cm=0.05 m Outer diameter of fin is : D2=6 cm=0.06 m…
Q: A 1 m long, 5 cm diameter, cylinder placed in an atmosphere of 40°C is provided with 12 longitudinal…
A: Given data as per question length of fin =2.5 cm Diameter of cylinder=5 cm The heat transfer…
Q: A steel fin (k = 54 W/m-K) with a cross-section of an equilateral triangle, 5 mm in side is 80 mm…
A:
Q: Q1 A composite house wall is constructed from 1.2 cm layer of fiber insulating board, an 8.0 cm…
A: Given Data
Q: The piston cylinder of a motorcycle engine is constructed of AISI 316 stainless steel, having a…
A: solution: The value of thermal conductivity of AISI 316 stainless steel as 15 W/m.K The heat…
Q: A domestic refrigeNator with inner dimensions of 0.7 m by 0.7 m at the base and height 1 m was…
A: Note:As per our guidelines we are supposed to answer only one question. Kindly repost other…
Q: A cold storage room is constructed of an inner layer of 12.7mm of pine, a middle inner of 101.6mm of…
A: Given, Ti = 255.4k To = 29701k Ki = 0.151 W/mk Km = 0.0433 W/mk Ko = 0.762 W/mk Li = 12.7 mm Lm =…
Q: An aluminum fins 1.5 cm wide and 1 mm thick are placed on a 2.5 cm diameter tube to dissipate the…
A: Given: Width of the aluminium fin (w)=1.5cm or 0.015mThickness of the aluminium fin (t)=1mmDiameter…
Q: 1. A pipe is covered with three insulation layers 250mm and 300mm and the respective thermal…
A:
Q: 2. A 15-cm X 20-cm hot surface at 85°C is to be cooled by attaching 4- cm-long aluminum ( k = 237…
A:
Q: A 15-mm radius pipe is going to be insulated with an insulation material (k=0.1 W/mK). The heat…
A: First, calculate the critical radius rc=kh=0.110=0.01 m=10 mm
Q: A pin fin of 2024-T6 aluminum has a length and diameter of 8.0 cm and 6.0 mm, respectively. The base…
A: Write the length of the fin. L=8 cm=8 cm×1 m100 cm=0.08 m Write the diameter of the fin. D=6…
Q: In determining the thermal conductivity of an insulating material, the temperatures were measured on…
A:
Q: Effectiveness of the infinitely long fin shows that. Choose the wrong statement If you increase…
A: Let us discuss about effectiveness in infinite long fin. Answer: None of above
Q: A 0.5 m x 2.5 m double-pane window consists of two 4.5-mm-thick layers of glass (k = 0.75 W/m·K)…
A: Area = 0.5 x 2.5 = 1.25 m2 glass thickness = 4.5 mm Air gap = 25 mm
Q: A steam pipe of 120-mm outside diameter is covered with a 20-mm-thick layer of calcium silicate…
A:
Q: The composite wall of a building consists of a 100 mm layer of common brick, a 100 mm layer of glass…
A:
Q: A large window glass 0.5 cm thick (k= 0.78 W/m K) is exposed to warm air at 25oC, over its inner…
A:
Q: 2) Urethane (k = 0.026 W/m-K) is used to insulate the sidewall and the top and bottom of a…
A: Given data as per question thermal conductivity of urethane(k)=0.026 wmkthickness=40mm=0.04 mheight…
What is the fin effectiveness of a rectangular plate fin made of aluminum O.3 mm thick mounted on a 16-mm-OD tube if the vertical tube spacing is 50 mm and the horizontal spacing is 40 mm? The air-side heat-transfer coefficient is 65 W/m2 • K, and the conductivity of aluminum is 202 W/m • K.
Ans. ƞ is 0. 72
Please provide a comprehensive step by step solution on how to get the answer.
Step by step
Solved in 2 steps with 2 images
- 2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from one side of an electronic device 1 m wide and 1 m tall. The fins are to be rectangular in cross section, 2.5 cm long and 0.25 cm thick, as shown in the figure. There are to be 100 fins per meter. The convection heat transfer coefficient, both for the wall and the fins, is estimated to be K. With this information determine the percent increase in the rate of heat transfer of the finned wall compared to the bare wall.1.10 A heat flux meter at the outer (cold) wall of a concrete building indicates that the heat loss through a wall of 10-cm thickness is . If a thermocouple at the inner surface of the wall indicates a temperature of 22°C while another at the outer surface shows 6°C, calculate the thermal conductivity of the concrete and compare your result with the value in Appendix 2, Table 11.An electronic device that internally generates 600 mW of heat has a maximum permissible operating temperature of 70C. It is to be cooled in 25C air by attaching aluminum fins with a total surface area of 12cm2. The convection heat transfer coefficient between the fins and the air is 20W/m2K. Estimate the operating temperature when the fins are attached in such a way that (a) there is a contact resistance of approximately 50 K/W between the surface of the device and the fin array and (b) there is no contact resistance (in this case, the construction of the device is more expensive). Comment on the design options.
- 1.4 To measure thermal conductivity, two similar 1-cm-thick specimens are placed in the apparatus shown in the accompanying sketch. Electric current is supplied to the guard heater, and a wattmeter shows that the power dissipation is 10 W. Thermocouples attached to the warmer and to the cooler surfaces show temperatures of 322 and 300 K, respectively. Calculate the thermal conductivity of the material at the mean temperature in W/m K. Problem 1.4One end of a 0.3-m-long steel rod is connected to a wall at 204C. The other end is connected to a wall that is maintained at 93C. Air is blown across the rod so that a heat transfer coefficient of 17W/m2 K is maintained over the entire surface. If the diameter of the rod is 5 cm and the temperature of the air is 38C, what is the net rate of heat loss to the air?A composite refrigerator wall is composed of 5 cm of corkboard sandwiched between a 1.2-cm-thick layer of oak and a 0.8-mm-thick layer of aluminum lining on the inner surface. The average convection heat transfer coefficients at the interior and exterior wall are 11 and 8.5W/(m2K) respectively. (a) Draw the thermal circuit. (b) Calculate the individual resistances of the components of this composite wall and the resistances at the surfaces. (c) Calculate the overall heat transfer coefficient through the wall. (d) For an air temperature of 1C inside the refrigerator and 32C outside, calculate the rate of heat transfer per unit area through the wall.
- 2.45 Heat is transferred from water to air through a brass wall . The addition of rectangular brass fins, 0.08 cm thick and 2.5 cm long, spaced 1.25 cm apart, is contemplated. Assuming a water-side heat transfer coefficient of and an airside heat transfer coefficient of , compare the gain in heat transfer rate achieved by adding fins to (a) the water side, (b) the air side, and (c) both sides. (Neglect temperature drop through the wall.)A high-speed computer is located in a temperature-controlled room at 26C. When the machine is operating, its internal heat generation rate is estimated to be 800 W. The external surface temperature of the computer is to be maintained below 85C. The heat transfer coefficient for the surface of the computer is estimated to be 10W/m2K. What surface area would be necessary to assure safe operation of this machine? Comment on ways to reduce this area.1.37 Mild steel nails were driven through a solid wood wall consisting of two layers, each 2.5-cm thick, for reinforcement. If the total cross-sectional area of the nails is 0.5% of the wall area, determine the unit thermal conductance of the composite wall and the percent of the total heat flow that passes through the nails when the temperature difference across the wall is 25°C. Neglect contact resistance between the wood layers.
- 2.9 In a large chemical factory, hot gases at 2273 K are cooled by a liquid at 373 K with gas-side and liquid-side convection heat transfer coefficients of 50 and , respectively. The wall that separates the gas and liquid streams is composed of a 2-cm thick oxide layer on the gas side and a 4-cm thick slab of stainless steel on the liquid side. There is a contact resistance between the oxide layer and the steel of . Determine the rate of heat loss from hot gases through the composite wall to the liquid.Consider a closed cylindrical reactor vessel of diameter D= 1 ft, and length L= 1.5 ft. The surface temperature of the vessel, T1, and the surrounding temperature, T2, are 390 deg. F and 50 deg. F, respectively. The convective heat transfer coefficient, h, between the vessel wall and surrounding fluid is 4.0 Btu/h . ft . ⁰F. Calculate the thermal resistance in ⁰F .h/Btu.12. A 3.1 cm long straight rectangular fin has a thickness of 2.7 mm. The thermal conductivity is 52 W/m K. The fin is attached to a wall maintained at 190 °C and is exposed to a convection environment at 40 °C and h- 31 W/m2 K. What is the fin efficiency? Express your answer in percent.