subject
Engineering, 29.10.2019 05:31 livirose1514

Ahollow aluminum sphere, with an electrical heater in the center, is used in tests to determine the thermal conductivity of insulating materials. the inner and outer radii of the sphere are 0.18 and 0.21 m, respectively, and testing is done under steady-state conditions with the inner surface of the aluminum maintained at 250°c. in a particular test, a spherical shell of insulation is cast on the outer surface of the sphere to a thickness of 0.15 m. the system is in a room for which the air temperature is 20°c and the convection coefficient at the outer surface of the insulation is 30 w/m2 ⋅ k. if 80 w are dissipated by the heater under steady-state conditions, what is the thermal conductivity of the insulation?

ansver
Answers: 1

Another question on Engineering

question
Engineering, 04.07.2019 18:10
Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.
Answers: 3
question
Engineering, 04.07.2019 18:20
Derive the correction factor formula for conical nozzle i=-(1+ cosa) and calculate the nozzle angle correction factor for a nozzle whose divergence hal-fangle is 13 (hint: assume that all the mass flow originates at the apex of the cone.
Answers: 3
question
Engineering, 04.07.2019 19:10
The sum of the normal stresses does not change as the stress state rotates through an angle. a)-trune b)- false
Answers: 2
question
Engineering, 04.07.2019 19:20
Liquid flows at steady state at a rate of 2 lb/'s through a pump, which operates to raise the elevation of the liquid 100 ft from control volume inlet to exit. the liquid specific enthalpy at the inlet is 40.09 btu/lb and at the exit is 40.94 btub. the pump requires 3 btu/s of power to operate. if kinetic energy effects are negligible and gravitational acceleration is 32.174 tt/s, the heat transfer rate associated with this steady state process is most closely 1)-2,02 btu/s from the liquid to the surroundings 2)-3.98 btu/s from the surroundings to the liquid. 3)-4.96 btu/s from the surroundings to the liquid. 4)-1.04 btu/s from the liquid to the surroundings.
Answers: 2
You know the right answer?
Ahollow aluminum sphere, with an electrical heater in the center, is used in tests to determine the...
Questions
question
Chemistry, 26.07.2019 18:40
question
History, 26.07.2019 18:40