Copper-coated, epoxy-filled fiberglass circuit boards are treated by heating a stack of them under high pressure, as shown in the sketch. The purpose of the pressing—heating operation is to cure the epoxy that bonds the fiberglass sheets, imparting stiffness to the boards. The stack, referred to as a book, is comprised of 10 boards and 11 pressing plates, which prevent epoxy from flowing between the boards and impart a smooth finish to the cured boards. In order to perform simplified thermal analyses, it is reasonable to approximate the book as having an effective thermal conductivity (k) and an effective thermal capacitance
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Introduction to Heat Transfer
- "You did calculations using the simplified HAZ time-temperature formulas, assuming 3D heat flow, and are presenting your final internship conclusions to management. You realize with horror, in the middle of your presentation, that you forgot to label your calculated curves (below). Which curve is which? Pick the best answer A: "Plot 1 is HYPERFILL® and Plot 2 is p-GMAW. Since HYPERFILL® has the higher heat input, it cools more slowly." B: "Plot 2 is HYPERFILL® and Plot 1 is p-GMAW. Since HYPERFILL® has the faster travel speed of the two processes, it cools faster." C: "Plot 1 is p-GMAW and Plot 2 is HYPERFILL®. Since p-GMAW has the slower travel speed, it cools more slowly." D: "Plot 2 is p-GMAW and Plot 1 is HYPERFILL®. Since p-GMAW has the lower heat input, it cools faster" Both (A) and (D)arrow_forwardTwo inches of urethane foam will reduce heat loss close to 1000% when applied to a 2-inch diameter uninsulated steel pipe. Assume the pipe wall thickness is 0.25-inches, the pipe interior convective heat loss (hi) is 500 BTU/hr-ft2-oF, and the pipe outside convective heat loss ho 20 BTU/hr-ft2-oF, k steel is 25 BTU/hr-ft-oF, and k insulaton is 0.023 BTU/hr-ft-oF. (hint - calculate heat loss with and without insulation.arrow_forwardOne of the ways to keep a pipe warm is by means of a steam tracer, through which an electrical resistance is used around the pipe and in a helical shape throughout its diameter?arrow_forward
- Review Conceptual Example 5 before attempting this problem. To illustrate the effect of ice on the aluminum cooling plate, consider the drawing shown here and the data contained therein. Ignore any limitations due to significant figures. (a) Calculate the heat per second per square meter that is conducted through the ice-aluminum combination. (b) Calculate the heat per second per square meter that would be conducted through the aluminum if the ice were not present. Notice how much larger the answer is in (b) as compared to (a). (a) Number i (b) Number i -10.0°C Units Units Ice -0.0050 m Aluminum -25.0°C 0.0015 marrow_forwardc) A steel pipe of 100 mm bore, and 10 mm bore thickness, carrying dry saturated steam at 28 bars, is insulated with a 40 mm layer of moulded insulation. This insulation in turn is insulated with a 60 mm layer of felt. The atmospheric temperature is 15 °C. Calculate: (i) the rate of heat loss by the steam per metre pipe length. (ii) the temperature of the outside Dimensions in mm surface.zzzzzzz h₂-15 W/m²K Steel k₁=50 W/mK AVALEHT Ø100 1₂ " Steam 28 bar h-550 W/m²K, Inner heat transfer coefficient = 550 W/m² K Outer heat transfer coefficient = 15 W/m² K Thermal conductivity of steel = 50 W/m K Thermal conductivity of felt = 0.07 W/m K Moulded insulation Felt Moulded insulation K₂=0.09 W/mK Thermal conductivity of moulded insulation = 0.09 W/m 40 10. A 60 15°C Felt K₁=0.07 W/mK zzzzzzzzarrow_forwardFor the 21.5-cm thick multilayer assembly as listed below, please estimate the temperature on the interface between material layers 3 and 4 Material layers - counted from the interior side: (1) 1.5 - cm gypsum board; (2) 4.0-cm - concrete of density - 2400-kg/m3; (3) 10-cm of XPS foam; (4) 6.0-cm - concrete of density - 2400-kg/m3 Interior film resistance is Ri = 0.121 m2K/W Exterior film resistance is Re - 0.029 m2K/W Internal temperature +20 degC External Temperature - 20 degCarrow_forward
- For the 21.5-cm thick multilayer assembly as listed below, please estimate the temperature on the interface between material layers 3 and 4 Material layers - counted from the interior side: (1) 1.5 - cm gypsum board; (2) 4.0-cm - concrete of density - 2400-kg/m3; (3) 10-cm of XPS foam; (4) 6.0-cm - concrete of density - 2400-kg/m3 Interior film resistance is Ri = 0.121 m2K/W Exterior film resistance is Re - 0.029 m2K/W Internal temperature +20 degC External Temperature - 20 degC All necessary material properties can be found in the ASHRAE Handbook of Fundamentals, or other sourcesarrow_forwardPlease help me get the correct answer quickly, please. :((arrow_forwardThe fuel assembly shown in the left figure consists of periodic arrays of annular bare fuel rods, which are cooled by passing water through the center of the rods as well as over the outer surface. We want to analyze the thermal performance of the fuel rods by dividing the assembly into a number of unit cells (control volumes) and evaluating the performance of a cell, as shown in the right figure.arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning