When operating at steady-state in a 250C room, the surface temperature of a 20 W incandescent light bulb is 1250C. Approximate the bulb as a 40 mm diameter sphere to estimate the rate of heat transfer from the bulb via convection. Air properties: k-0.030 W/m-K Spear surface area: S-4tr² v-20.92x10 m³/s Sphere volume: V-(4/3) Pr=0.700

When operating at steady-state in a 250C room, the surface temperature of a 20 W incandescent light bulb is 1250C. Approximate the bulb as a 40 mm diameter sphere to estimate the rate of heat transfer from the bulb via convection. Air properties: k-0.030 W/m-K Spear surface area: S-4tr² v-20.92x10 m³/s Sphere volume: V-(4/3) Pr=0.700

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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1.1 Determine the electrical power supplied to a boiler when the temperature of the enteringwater is 20 C and the exiting temperature is 89 C. The flow of.the pressured water is 2 Kg/s. There is anegligible pressure drop through this boiler and it operates at a constant pressure of 3 bars. The specificheat is c = 4,370 J/(Kg K). There is a 1.5(105) W rate of heat loss from the boiler during this process to asurrounding at 293.2 k. Consider steady state conditions.1.2 Calculate the total rate of entropy production in Problem 1.1.1.3 Calculate the total rate of exergy destruction (W) in Problem 1.1. The dead statetemperature is 293.2 K and pressure is 1 bar.1.4 Calculate the mass flowrate of fuel (natural gas, CH4) required to heat the water flow to theconditions of problem 1.1 if the electrical heating device is replaced with a gas fired boiler. The highheating value (HHV) of the fuel is 50.02 MJ/kg.1.5 Calculate the exergy destroyed in the process described by problem 1.4. The exergy…
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