Air surrounding a light bulb is moving at 25 m/sec. The surrounding conditions are kept at atmospheric pressure and at temperature 25o C. The light bulb external surface is kept at 140o C. What is the heat transfer rate from the light bulb to the surrounding? Assume the light bulb as a sphere with a diameter of 50 mm

Air surrounding a light bulb is moving at 25 m/sec. The surrounding conditions are kept at atmospheric pressure and at temperature 25o C. The light bulb external surface is kept at 140o C. What is the heat transfer rate from the light bulb to the surrounding? Assume the light bulb as a sphere with a diameter of 50 mm

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.

Chapter5: Analysis Of Convection Heat Transfer

Section: Chapter Questions

Problem 5.32P

See similar textbooks

Similar questions

Subject : Thermofluid Question : A wind turbine four 10 cm diameter cups with a center-to-center distance of 40 cm, as shown in Figure 4. Due to a malfunction, the pivot is suddenly stuck, and the cups stop rotating. If the wind speed is 12 m/s moving at the described direction and air density is 1.25 kg/m3. Determine the maximum torque this turbine applies on the pivot.
A fire hose is shooting water at a refrigerator at 10 kg/s with a velocity of 10 m/s. This flow is perpendicular to the surface and all water flows off parallel to the surface (ie no "x" direction in outflow). The friction on the ground which must be overcome to cause the refrigerator to move is 50 N. The refrigerator is 2 m tall and 0.8m wide and 1 m deep. It weights 200 kg (which you may assume to be evenly distributed). Will it move? If no what is the initial acceleration?
An air cannon uses compressed air to propel a projectile from rest to a final velocity. Consider an air cannon that is to accelerate a 10-gram projectile to a speed of 300 m/s using compressed air, whose temperature cannot exceed 20°C. The volume of the storage tank is not to exceed 0.1 m3 . Select the storage volume size and maximum storage pressure that require the minimum amount of energy to fill the tank.
In a piping system at sea level, a liquid of relative density 1.5 flows through a pipe 8 cm in diameter.diameter at 1.2 m/s. Fifteen meters above the pipe diameter is reduced to 5 cm, Assume that the temperature of thefluid in the process remains at 30°C, producing a heat loss of 25 N-m/kg. Determine the pressure change in the thermodynamic process.
A 1.5m diameter spherical balloon containing air at (K + 10) kPa is cooled such that the volume is reduced by 25%. For the process, the pressure is proportional to the square of the sphere’s diameter. What is the work done by the surrounding? K=162
A 6 kg/s of hot liquid flow continuously without leaking in a 40 mm inside diameter with thickness of 7 mm pipe with temperature of 50℃. Thermal conductivity of pipe is 10W/(m℃) and surface conductance of liquid is 9W/(m^2℃). The outer fluid has temperature of 25℃ and surface conductance of 6W/(m^2℃). Cp of hot liquid = 4.2KJ/(Kg℃). Find the minimum length of pipe in meters just to cool down the hot liquid as much as possible if the maximum heat transfer is the constant heat transfer throughout the pipe.
A box with a mass of 3m is on frictionless ground, attached to a wall (on the left-side of the box) by a spring with constant k. Inside the box (on the frictionless floor of the box), is a block of mass m. The block is also attached to the left-side of the box (but inside it), by a second spring, with a spring constant 2k/5.1) What are the F = ma equations for the box and the block? (Remember how the motion of each, affects each other)2) What are the matrices K and M for the system?3) What are the normal frequencies of the system?4) Describe the motion of the masses. In phase? Out of phase? Does one mass oscillate with a higher amplitude than the other?
The bottom quarter of a vertical cylindrical tank of total height 0.4 m and diameter is filled with a liquid (SG>1, like glycerin) and the ret with water. The tank is now rotated about its vertical axis at constant angular speed w. Determine the value of angular speed in rad/s when point P on the axis at the liquid-liquid interface touches the bottom of the tank. Include the free body diagram in your solution. a.12.1 b.10.3 c.14.4 d.13.2
A mass of 200 kg of water at 20°C is stored in a tank. An engine coupled to a propeller inside the tank transfers energy into the water causing it to heat up. What will be the water temperature after two hours with the engine running continuously? It is known that the engine power is 5 HP. (1 HP ≅ 0.75 kW). Take it out that the system has perfect thermal insulation.
A gasoline engine is at a location where the temperature is measured to be 14.2 °C and produces 347 KW at 5800 rpm while consuming 0.0184 kg's of fuel. During operation, data shows that its mechanical energy loss is 18 %, the actual volume of air going into each cylinder is 80% (the volumetric efficiency has a negligible variation), and the actual fuel-to-air ratio is 0.065. What were the engine parameters at sea level conditions if the pressure here is 100.3 kPa and the temeratur here is 18 Uc hotter than that of the alevated conditions? Determine at sea-level conditions the ISFC in ka/kW-hr Use four (4) decimal places in your solution and answer.
A gasoline engine is at a location where the temperature is measured to be 14.2 °C and produces 347 KW at 5800 rpm while consuming 0.0184 kg's of fuel. During operation, data shows that its mechanical energy loss is 18 %, the actual volume of air going into each cylinder is 80% (the volumetric efficiency has a negligible variation), and the actual fuel-to-air ratio is 0.065. What were the engine parameters at sea level conditions if the pressure here is 100.3 kPa and the temeratur here is 18 Uc hotter than that of the alevated conditions? Determine at sea-level conditions the ISFC in ka/kW-hr
It is important for the body to be able to cool itself even duringmoderate exercise. Suppose a 70kg man runs on a treadmill for 30min and at a (total)metabolic energy expenditure rate of 1000W. Suppose also that the man cannot perspire; and cannot lose any heat viaconduction, convection and radiation (as would be the case with astronauts wearing theirair-tight spacesuit but w/o portable cooling unit). By how much would the man’s bodytemperature increase at the end of the 30min exercise? Express your answer in oC. A) 0.5B) 1.4C) 3.1D) 5.7E) 8.8