An air heater may be fabricated by coiling Nichrome wire and passing air in cross flow over the wire. Consider a heater fabricated fromwire of diameter D = 1 mm, electrical resistivity pe = 106 Q-m, thermal conductivity k = 25 W/m-K, and emissivity & = 0.2. Theheater is designed to deliver air at a temperature of T = 350°C under flow conditions that provide a convection coefficient of h =350 W/m²-K for the wire. The temperature of the housing that encloses the wire and through which the air flows is Tsur = 50°C. (a) Ifthe maximum allowable temperature of the wire is Tmax = 1200°C, what is the maximum allowable electric current I? If themaximum available voltage is AE = 110 V, what is (b) the corresponding length L of wire that may be used in the heater and (c) thepower rating of the heater? Hint: In your solution, assume negligible temperature variations within the wire, but after obtaining thedesired results, assess the validity of this assumption.Wire(D, L,Pe, k,&, Tmax)↑1-Housing, Tsur0 0 0 0 0 0 0- ΔΕ(a) Imax(b) L ==(c) Pelec =iiiAmkWAirTh

The answer has been attached in the form of images as follows:

Answered: An air heater may be fabricated by…

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.

Chapter9: Heat Transfer With Phase Change

Section: Chapter Questions

Problem 9.33P

See similar textbooks

Similar questions

6.3 Steam at 100 kPa and is flowing across a 5-cm- OD tube at a velocity of 6 m/s. Estimate the Nusselt number, the heat transfer coefficient, and the rate of heat transfer per meter length of pipe if the pipe is at .
Define: a. Convection heat transfer coefficient b. Loss of pressure across the tube arrangement *)Based on image below:
Refrigerant-134a is being transported at 0.08 kg/s through a Teflon tube of inside diameter D; = 20 mm and outside diameter Do = 25 mm, while atmospheric air at V = 28 m/s and 300 K is in cross flow over the tube. What is the heat transfer per unit length of tube, in W/m, to Refrigerant-134a at 230 K? q' = i W/m Use Hilpert correlation to estimate the external heat transfer coefficient, and please state ALL assumptions.
Q/ A composite wall is formed of a 2.5-cm copper plate (k = 386 W/m.°C), a 3.2-mm layer of 0.038 W/m.°C). The wall is asbestos (k = 0.16 W/m.°C), and a 5-cm layer of fiberglass (k subjected to an overall temperature difference of 560-C. Calculate the heat flow per unit area
A square isothermal chip is of width 5mm on a side mounted in a substrate such that its side and back surfaces are well insulated, while the front surface is exposed to the flow of coolant at 15C. From reliability considerations, the chip temperature must not exceed 85C. If air is used as a coolant, h = 200W/m2. If a dielectric liquid is used as coolant, h = 3000W/m2. What is the difference in maximum allowable power through the chip between the two coolants? (answer in W) *
Please show all steps, not Ai generated, has been wrong before. I need to understand the process.
Heat transfer Air flows through a smooth thin-walled rectangular duct of height, a= 0.3 m and width, b=1 m. The air is heated by the duct walls at a uniform heat flux of 250 W/m2 . At some location inside the duct, the mean velocity and temperature of air was measured to be um = 0.05 m/s and Tm = 350 K, respectively. (a) What is the hydraulic diameter of the duct? (b) What is the Reynolds number for the flow in the duct? (c) Is the flow laminar or turbulent? (d) Assuming fully developed flow, what is the heat transfer coefficient (h) at this location?
Water at T, = 24°C is heated to T, = 74°C by passing it through an alternating 2. array of tubes. The outer diameter of the tube D = 2.5 cm and is maintained at a uniform surface temperature Ts = 100°C. The transverse and longitudinal pits are: SL =1,5; = 2. D The row of tubes in the flow direction for heating water is 10, and the free flow speed of water before entering the tube beam is 0.3 m/s. Determine the heat transfer coefficient.
Typically, air is heated in a hair dryer by blowing it across a coiled wire through which an electric current is passed. Thermal energy is generated by electric resistance heating within the wire and is transferred by convection from the surface of the wire to the air. Consider conditions for which the wire is initially at room temperature, T;, and resistance heating is concurrently initiated with airflow att = 0. q Air Too, h 001 Coiled wire (ro, L, k, p, cp) 0000 Pelec Airflow ווי SU
please very urgent i need the right answer please be carfully
can you please work it all please please
Engine oil is heated by flowing through a circular tube of diameter D = 50 mm and length L = 25 m and whose surface is maintained at 150°C. (a) If the flow rate and inlet temperature of the oil are 0.5 kg/s and 20°C, what is the outlet temperature Tm,o? What is the total heat transfer rate q for the tube?

SEE MORE QUESTIONS

Recommended textbooks for you

Principles of Heat Transfer (Activate Learning wi…

Mechanical Engineering

ISBN:

9781305387102

Author:

Kreith, Frank; Manglik, Raj M.

Publisher:

Cengage Learning