please solve and show work 3-90 A 2.2-mm-diameter and 14-m-long electric wire is tightly wrapped with a 1-mm-thick plastic cover whose thermal conductivity isk = 0.15 W/m.K. Electrical measurements indicate that a current of 13 A passes through the wire, and there is a voltage drop of 8 Valong the wire. If the insulated wire is exposed to a medium at T = 30°C with a heat transfer coefficient of h = 24 W/m²·K, determinethe temperature at the interface of the wire and the plastic cover in steady operation. Also determine if doubling the thickness of theplastic cover will increase or decrease this interface temperature.ElectricalwireT∞ = 30°CInsulation14 m

Step 1:Draw the thermal network. Calculate the outer convection resistance:Rc=πd2Lh1…

Answered: 3-90 A 2.2-mm-diameter and 14-m-long…

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter4: Numerical Analysis Of Heat Conduction

Section: Chapter Questions

Problem 4.12P

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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.
One 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?
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 1.4
A 90-amp electric current is flowing through a 6-mm diameter lead wire. The thermal conductivity of the lead is k= 32 W/m K and the electrical resistance per unit length of the wire is R' = 0.0073 /m. The outer surface of the lead wire is exposed to 40°C air with a convection heat transfer coefficient of h=12 W/m².K. Find the temperature at the center of the lead wire.
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