Concept explainers
The composite insulation shown, which was described in Chapter 1 (Problem 1.86e), is being considered as a ceiling material.
It is proposed that the outer and inner slabs be made from low-density particle board of thicknesses
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Check out a sample textbook solutionChapter 13 Solutions
Fundamentals of Heat and Mass Transfer
Additional Engineering Textbook Solutions
Vector Mechanics for Engineers: Dynamics
Mechanics of Materials, 7th Edition
Heat and Mass Transfer: Fundamentals and Applications
INTERNATIONAL EDITION---Engineering Mechanics: Statics, 14th edition (SI unit)
DESIGN OF MACHINERY
Shigley's Mechanical Engineering Design (McGraw-Hill Series in Mechanical Engineering)
- You are asked to design an insulated stud timber wall and have the following materials available: Outer skin materials. ● Plasterboard 8 mm thick (k= 0.3 W/m.K) Plasterboard 12.5 mm thick (k = 0.3 W/m.K) Insulated Plasterboard 25 mm thick (k = 0.2 W/m.K) Timber studs available (k = 0.1 W/m.K) 50 mm x 100 mm 50 mm x 120 mm 50 mm x 150 mm Insulation layers Glass fibre insulation (k= 0.05 W/m.K) ● Polyisocyanurate insulation (k= 0.025 W/m.K) Sheeps wool insulation (k= 0.04 W/m.K) ● Wall construction should consist of two outer plasterboard skins, followed by an appropriate stud/insulation infill layer. Studs can be placed vertically at 400 mm or 600 mm intervals and you may ignore any requirement for horizontal studding. 1) Draw a plan (top view) cross section of your wall indicating dimensions, spacing and material choices. 2) Calculate the thermal resistance of your wall. 3) If the internal convective heat transfer coefficient in room one is 10 W/m²K and in the second room it is 15…arrow_forwardTo 8. Ti 1. 2. 3. 4" Common Brick 1/2" OSB Sheathing 3-1/2" x 1-1/2" (2x4) Yellow Pine Studding placed on 16" center 4. 5. 3-1/2" Figerglass Insulation 1/2" Drywall A wall of a house as shown in the accompanying sketch is 10 ft. high and 30 ft. long and has no windows. The outside heat transfer coefficient, h., is 6.0 Btu/hr ft2°F and the inside convective heat transfer coefficient hi is 1.45 Btu/hr ft2°F. 6. Calculate the heat loss through the wall if the house is heated such that the room air temperature, Ti, is 70°F on a day when the outside air temperature, T., is 0°F. State all assumptions and list the thermal resistances and thermal conductivities for 3 each selection of the wall. 7. For this problem, what would be the value of the overall heat transfer coefficient, U? Ans: U = 0.056 Btu/hr ft2ºF You are asked to design a metal hot dog holder for roasting hot dogs over an open campfire. The holder is to be designed such that while the end holding the hot dog becomes cherry red…arrow_forward1. An element of graphite-reinforced composite is completely dry and is constrained against any dimensional changes in the 1 and 2 directions, but it is free to expand in the 3 direction. The element absorbs 1.5% of its dry weight in the form of moisture. (a) What is the strain in the 3 direction as a result of the moisture absorption? Why is this strain different from the value given by B3AM? (b) What stresses develop in the element? Assume that moisture absorption does not influence the material properties.arrow_forward
- b) A steel pipe of 100mm bore and 7mm thickness transports steam at 260 °C. The pipe is insulated with 40mm of a molded high temperature diatomaceous earth covering. This covering is in turn insulated with 60mm of asbestos. If the atmospheric temperature is 25 °C, calculate the rate at which heat is lost by the steam per meter length of the pipe.arrow_forwardAn eyed plate & pin is assembled as illustrated and are subjected to an opposing force of 10KN. The rod diameter & plate thickness is 6mm. The width of the plate is 20mm. A hole to which the pin is inserted is 8mm in diameter is located at the center of the plate. The plate is made of annealed SAE 1025 & the pin is high-heat oil quenched SAE 1095. (a) Determine if the assembly is safe to use; otherwise (b) Determine the safe load of the assembly.arrow_forwardA cold storage room has a wall consists of an inside finish of 0.60 in cement plaster(k = 0.67), two layers of corkboard each 2.5 in thick (k = 0.03) and an outside layer of building tile. The value of U for the entire wall is 0.058, the internal air filmcoefficient is 1.65, the inner temperature is 23°F and the outside temperature is85°F. Calculate the heat flow through the unit wall area, Btu/hr.ft2A. 1.47 B. 2.47 C. 3.47 D. 4.47arrow_forward
- A continuous and aligned fibrous reinforced composite having a cross-sectional area of 975 mm, then the area is subjectedi to an extenal tensile load. If the stresses sustained by the fibre and matrix phases are 215 MPa and 5.38 MPa, respectively, the force sustained by the fibre phase is 76,800 N, and the total longitudinal composite strain is 1.56x103 then determine.arrow_forwardA wall measures (9x3) m2 and it consists of the following layers, the wall has one door and two windows with an area of 1.8 m2 and 3.5 m2, respectively. The wall consists of the following layers: (1) Hard stone of 70 mm thickness and k = 1.7 W/m.°C. (2) Concrete of 200 mm thickness and k = 1.75 W/m.°C. (3) Polystyrene of 50 mm thickness and k = 0.04 W/m.°C. (4) Plaster of 20 mm thickness and k = 1.25 W/m.°C. The inside and outside design conditions are (22°C, 50% RH) , and (7 °C, 90% RH) respectively, and the inside and outside film resistances are 0.12 and 0.03 m2.°C/W, respectively. Calculate the following: (a) Heat loss through the wall (b) Inside wall surface temperature. (c) Heat loss with no insulation, will the water vapor condense on the wall?arrow_forwardQuestion 1 A composite component is comprised of a tube and a concentric rod running inside it, both with a length of 1.5 meters. The tube is made of copper and has inner and outer diameters of 60 mm and 100 mm, respectively, a coefficient of thermal expansion and elastic modulus of 17 ×10-6C and 117 GPa, respectively. The rod is made of aluminium with a diameter, coefficient of thermal expansion and elastic modulus of 50 mm, 23 x10-6C and 80 GPa, respectively. If the composite is exposed to a temperature rise of 120°C, determine: 1.1 The sense and magnitude of the stresses induced in the composite if it is not restrained. 1.2 The sense and magnitude of the stresses induced in the composite if it is partially restrained with an allowed free expansion of 0.3 mm.arrow_forward
- 1.A composite component is comprised of a tube and a concentric rod running inside it, both with a length of 1.5 meters. The tube is made of copper and has inner and outer diameters of 60 mm and 100 mm, respectively, a coefficient of thermal expansion and elastic modulus of 17 ×10−6? and 117 GPa, respectively. The rod is made of aluminium with a diameter, coefficient of thermal expansion and elastic modulus of 50 mm, 23 ×10−6? and 80 GPa, respectively. If the composite is exposed to a temperature rise of 120°C, determine:1.1 The sense and magnitude of the stresses induced in the composite if it is not restrained. 1.2 The sense and magnitude of the stresses induced in the composite if it is partially restrainedwith an allowed free expansion of 0.3 mm.arrow_forwardFloor joists are structural members which support flooring in structures, as in the diagram on the right. The floor sits upon the minor length of the joist, and the joists are set at equal spacing to reach the desired floor stiffness. How many 2x6 joists would it take to equal the floor stiffness of the same floor supported by ten (10) 2x12 joists of the same species?arrow_forwardTo 8. 22 1 2 T₁ 3 1. 2. 3. 4" Common Brick 1/2" OSB Sheathing 3-1/2" x 1-1/2" (2x4) Yellow Pine Studding placed on 16" center 4. 5. 3-1/2" Figerglass Insulation 1/2" Drywall A wall of a house as shown in the accompanying sketch is 10 ft. high and 30 ft. long and has no windows. The outside heat transfer coefficient, h., is 6.0 Btu/hr ft2°F and the inside convective heat transfer coefficient hi is 1.45 Btu/hr ft²°F. 6. Calculate the heat loss through the wall if the house is heated such that the room air temperature, Ti, is 70°F on a day when the outside air temperature, T., is 0°F. State all assumptions and list the thermal resistances and thermal conductivities for each selection of the wall. For this problem, what would be the 7. value of the overall heat transfer coefficient, U? Ans: U = 0.056 Btu/hr ft2°F You are asked to design a metal hot dog holder for roasting hot dogs over an open campfire. The holder is to be designed such that while the end holding the hot dog becomes cherry…arrow_forward
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