A stainless steel ball (? = 8055 kg/m3 , CP = 480 J/Kg? K ) of...

A stainless steel ball (? = 8055 kg/m³ , C_P = 480 J/Kg? K ) of diameter D = 15cm is removed from the oven at a uniform temperature of 350 Degrees C. The ball is then subjected to the flow of air at 1 atm pressure and 30 degrees C with a velocity of 6m/s. The surface temperature of the ball eventually drops to 250 degrees 250 degrees C. Determine the average convection heat transfer coefficient during this cooling process and estimate how long this process has taken. The solution should be h = 25.12 W/m2 C and time = 1425 seconds according to the professor.

Solutions

Expert Solution

samet mamat answered 1 year ago

Next > < Previous

Related Solutions

A thick steel slab (ρ= 7800 kg/m3, c= 480 J/kg·K, k= 50 W/m·K) is initially at...

A thick steel slab (ρ= 7800 kg/m3, c= 480 J/kg·K, k= 50 W/m·K) is initially at 300°C and is cooled by water jets impinging on one of its surfaces. The temperature of the water is 25°C, and the jets maintain an extremely large, approximately uniform convection coefficient at the surface. Assuming that the surface is maintained at the temperature of the water throughout the cooling, how long will it take for the temperature to reach 50°C at a distance of...

FIreclay brick (ρ=2050 kg/m3, cp=960 J/kg-K, k=1.1 W/m-K) with dimensions 0.06 m x 0.09 m x...

FIreclay brick (ρ=2050 kg/m3, cp=960 J/kg-K, k=1.1 W/m-K) with dimensions 0.06 m x 0.09 m x 0.20 m is removed from a kiln at 1600K and cooled in air at 40C with h = 30 W/m2-K. What is the temperature at the corner of the brick after 50 minutes of cooling? Give your answer in degrees C.

Water ( ρ= 1000 kg/m3; Cp= 4.2 kJ/kg.K; k= 0.58 W/m.K ) at 1,537 kg/hr and...

Water ( ρ= 1000 kg/m3; Cp= 4.2 kJ/kg.K; k= 0.58 W/m.K ) at 1,537 kg/hr and 26oC enters a 10-mm-diameter smooth tube whose wall temperature is maintained at 79oC. If the water's Nusselt number (Nu) = 375, and the tube length is 7.6, calculate the water outlet temperature,in oC.

Consider a turbine; working substance is air. cp=1.0 kJ/kgK , k=1.4 v1=0.03 , v2=0.08 m3/kg , ...

Consider a turbine; working substance is air. cp=1.0 kJ/kgK , k=1.4 v1=0.03 , v2=0.08 m3/kg , p1=2.5 bar; state 1 is enterance, state 2 is the exit of the turbine. The turbine is not ideal (isentropic); the air goes through a state change according to pv^n=constant , n=1.6 Compute the ideal and actual specific works and turbine efficiency. pvn=constant , n=1.6

For a ball bearing made out of plastic inner and outer race and a stainless steel...

For a ball bearing made out of plastic inner and outer race and a stainless steel ball, which of these materials is likely to wear? What would the wear pattern be like? Which will eventually fail first?

For H2O, determine the specific volume at the indicated state, in m3/kg. (a) T = 480°C,...

For H2O, determine the specific volume at the indicated state, in m3/kg. (a) T = 480°C, p = 20 MPa. (b) T = 160°C, p = 20 MPa. (c) T = 40°C, p = 2 MPa.

A crane drops a 0.30 kg steel ball onto a steel plate.

A crane drops a 0.30 kg steel ball onto a steel plate. The ball's speeds just before impact and after are 4.5 m/s and 4.2 m/s, respectively. If the ball is in contact with the plate for 0.030 s, what is the magnitude of the average force that the ball exerts on the plate during impact?

Water (cp=4179 J/kg·K) at 30 °C flows on the inside of a steel tube with 25...

Water (cp=4179 J/kg·K) at 30 °C flows on the inside of a steel tube with 25 mm inner diameter and 0.4 mm wall thickness at a flow rate of 0.4 kg/s. The tubes forms inside of a counter flow double pipe heat exchanger. Engine oil at 100 °C flows in the annular space with a flowrate of 0.1 kg/s. The outlet temperature of the oil is 60 °C. The material of the heat exchanger is carbon steel with k=45 W/m·K....

3. A stainless steel sphere of thermal conductivity 16 W/m · K with a diameter of...

3. A stainless steel sphere of thermal conductivity 16 W/m · K with a diameter of 4 cm is exposed to a convective environment of 15 W/m2 · K, 20?C. Heat is generated uniformly in the sphere at a rate of 1.0 MW/m3 . Determine the steady-state temperature of the sphere at its center and its surface. Also determine the heat flux at a radius of 1.5 cm.

The strength coefficient (K) and the work hardening exponent (n) for a stainless steel were determined...

The strength coefficient (K) and the work hardening exponent (n) for a stainless steel were determined during the analysis of the data from a tensile test using a standard tensile specimen. The flow curve parameters for the stainless steel are K= 1250 MPa and n = 0.4. A compression test is performed on a specimen of the stainless steel. If the starting height and diameter of the specimen are 80 mm and 18 mm, respectively and the final height of...

Subjects