In the production of sheet metals or plastics, it is custom- ary to cool the material before it leaves the production process for storage or shipment to the customer. Typi- cally, the process is continuous, with a sheet of thickness 8 and width W cooled as it transits the distance L between two rollers at a velocity V. In this problem, we consider cooling of plain carbon steel by an airstream moving at a velocity u. in cross flow over the top and bottom surfaces of the sheet. A turbulence promoter is used to provide tur- bulent boundary layer development over the entire surface. Ti 8 Turbulence romoter W + Surroundings, Tsur Air uoo X Too Plain carbon steel L Vv (a) By applying conservation of energy to a differential control surface of length dx, which either moves with the sheet or is stationary and through which the sheet passes, and assuming a uniform sheet temperature in the direction of airflow, derive a dif- ferential equation that governs the temperature dis- tribution, T(x), along the sheet. Consider the effects of radiation, as well as convection, and express your result in terms of the velocity, thickness, and properties of the sheet (V, S, p, C., &), the average convection coefficient hw associated with the cross flow, and the environmental temperatures (T., Tsur). (b) Neglecting radiation, obtain a closed form solution to the foregoing equation. For 8 = 3 mm, V = 0.10 m/s, L = 10 m, W = 1 m, u = 20 m/s, T = 20°C, and a sheet temperature of T, = 500°C at the onset of cooling, what is the outlet temperature T? Assume a negligible effect of the sheet velocity on bound- ary layer development in the direction of airflow. The density and specific heat of the steel are p = 7850 kg/m³ and = 620 J/kg K, while properties Cp of the air may be taken to be k 0.044 W/m K, v=4.5 × 105 m²/s, Pr = 0.68. . =
In the production of sheet metals or plastics, it is custom- ary to cool the material before it leaves the production process for storage or shipment to the customer. Typi- cally, the process is continuous, with a sheet of thickness 8 and width W cooled as it transits the distance L between two rollers at a velocity V. In this problem, we consider cooling of plain carbon steel by an airstream moving at a velocity u. in cross flow over the top and bottom surfaces of the sheet. A turbulence promoter is used to provide tur- bulent boundary layer development over the entire surface. Ti 8 Turbulence romoter W + Surroundings, Tsur Air uoo X Too Plain carbon steel L Vv (a) By applying conservation of energy to a differential control surface of length dx, which either moves with the sheet or is stationary and through which the sheet passes, and assuming a uniform sheet temperature in the direction of airflow, derive a dif- ferential equation that governs the temperature dis- tribution, T(x), along the sheet. Consider the effects of radiation, as well as convection, and express your result in terms of the velocity, thickness, and properties of the sheet (V, S, p, C., &), the average convection coefficient hw associated with the cross flow, and the environmental temperatures (T., Tsur). (b) Neglecting radiation, obtain a closed form solution to the foregoing equation. For 8 = 3 mm, V = 0.10 m/s, L = 10 m, W = 1 m, u = 20 m/s, T = 20°C, and a sheet temperature of T, = 500°C at the onset of cooling, what is the outlet temperature T? Assume a negligible effect of the sheet velocity on bound- ary layer development in the direction of airflow. The density and specific heat of the steel are p = 7850 kg/m³ and = 620 J/kg K, while properties Cp of the air may be taken to be k 0.044 W/m K, v=4.5 × 105 m²/s, Pr = 0.68. . =
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 5.54P
Related questions
Question
Please show all steps not Ai generated I need to understand the process
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
This is a popular solution!
Trending now
This is a popular solution!
Step by step
Solved in 5 steps with 5 images
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Recommended textbooks for you
Principles of Heat Transfer (Activate Learning wi…
Mechanical Engineering
ISBN:
9781305387102
Author:
Kreith, Frank; Manglik, Raj M.
Publisher:
Cengage Learning
Principles of Heat Transfer (Activate Learning wi…
Mechanical Engineering
ISBN:
9781305387102
Author:
Kreith, Frank; Manglik, Raj M.
Publisher:
Cengage Learning