Thermodynamics HW Solutions 65

Thermodynamics HW Solutions 65 - Chapter 1 Basics of Heat...

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Chapter 1 Basics of Heat Transfer 1-125 Water is to be heated steadily from 15°C to 50°C by an electrical resistor inside an insulated pipe. The power rating of the resistance heater and the average velocity of the water are to be determined. Assumptions 1 This is a steady-flow process since there is no change with time at any point within the system and thus ΔΔ mE CV CV and = = 00 ,. 2 Water is an incompressible substance with constant specific heats. 3 The kinetic and potential energy changes are negligible, Δ Δ ke pe 0 . 4 The pipe is insulated and thus the heat losses are negligible. Properties The density and specific heat of water at room temperature are ρ = 1000 kg/m 3 and C = 4.18 kJ/kg·°C (Table A-9). Analysis ( a ) We take the pipe as the system. This is a control volume since mass crosses the system boundary during the process. Also, there is only one inlet and one exit and thus . The energy
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This note was uploaded on 01/14/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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