Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470917855
Author: Bergman, Theodore L./
Publisher: John Wiley & Sons Inc
expand_more
expand_more
format_list_bulleted
Videos
Question
Chapter 9, Problem 9.115P
To determine
The minimum value of the convection heat transfer coefficient.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
The onset of free convection. Plastic shrink wrap can be used to insulate windows by trapping air between your window and the wrapping. Calculate the critical gap width between the plastic and the window at which free convection will occur on an average winter’s day, when the outside temperature is 41°F and the inside temperature is 68°F. Would you expect there to be more or less heat transfer when the spacing is above this gap? Explain.
Take your time for solving problem. But also take the proper given values and solve the problem correctly.
Question One
Explain how heat is transferred from one point to another illustrating with appropriate diagram.
Calculate the heat flow per square meter (heat flux) through water medium with thermal conductivity of 0.6, flowing in a 5 cm thickness space, if the temperatures on the two surfaces are 50 and 210°C, respectively.
Question 2
Distinguish between force and free convection with the aid of appropriate illustrations.
What is the approximate temperature difference between a hot plate and the surrounding air if the heat flux from the plate is 800 W/m2? Assume that the air is flowing past the surface with a velocity of 5 m/s giving a heat transfer coefficient of 20 W/(m2K).
Question 3
Explain the differences between laminar and turbulent flow
Water (ν = 0.86x10-6m2/s) flows through a tube with the diameter 12 mm at a velocity of 2 m/s. Determine if the flow is laminar or turbulent!
Chapter 9 Solutions
Fundamentals of Heat and Mass Transfer
Ch. 9 - The one-dimensional plane wall of Figure 3.1 is of...Ch. 9 - Using the values of density for water in Table...Ch. 9 - Consider an object of Characteristic length 0.01 m...Ch. 9 - To assess the efficacy of different liquids for...Ch. 9 - In many cases, we are concerned with free...Ch. 9 - The heat transfer rate due to free convection from...Ch. 9 - Consider a large vertical plate with a uniform...Ch. 9 - For laminar free convection flow on a vertical...Ch. 9 - Consider an array of vertical rectangular tins,...Ch. 9 - A number of thin plates are to be cooled by...
Ch. 9 - Prob. 9.11PCh. 9 - Prob. 9.13PCh. 9 - The plate described in Problem 9.14 has been used...Ch. 9 - Determine the average convection heat transfer...Ch. 9 - Consider a vertical plate of dimension 0.025m0.50m...Ch. 9 - During a winter day, the window of a patio door...Ch. 9 - Prob. 9.20PCh. 9 - A household oven door of 0.5-m height and 0.7-m...Ch. 9 - Consider a vertical, single-pane window of...Ch. 9 - Consider laminar flow about a vertical isothermal...Ch. 9 - Consider the conveyor system described in Problem...Ch. 9 - Prob. 9.25PCh. 9 - Consider an experiment to investigate the...Ch. 9 - The vertical rear window of an automobile is of...Ch. 9 - Prob. 9.28PCh. 9 - Prob. 9.29PCh. 9 - Prob. 9.30PCh. 9 - A refrigerator door has a height and width of...Ch. 9 - In the central receiver concept of a solar power...Ch. 9 - Prob. 9.34PCh. 9 - Airflow through a long, 0.2-m-square air...Ch. 9 - Prob. 9.36PCh. 9 - An electrical heater in the form of a horizontal...Ch. 9 - Consider a horizontal 6-mm-thick, 100-mm-long...Ch. 9 - Prob. 9.39PCh. 9 - Prob. 9.40PCh. 9 - Prob. 9.41PCh. 9 - Many laptop computers are equipped with thermal...Ch. 9 - Prob. 9.43PCh. 9 - At the end of its manufacturing process, a silicon...Ch. 9 - Integrated circuit (IC) boards are stacked within...Ch. 9 - Prob. 9.48PCh. 9 - Prob. 9.50PCh. 9 - Prob. 9.51PCh. 9 - Prob. 9.52PCh. 9 - Prob. 9.53PCh. 9 - Prob. 9.54PCh. 9 - Prob. 9.55PCh. 9 - Prob. 9.56PCh. 9 - Prob. 9.57PCh. 9 - A horizontal tube of 12.5-mm diameter with an...Ch. 9 - Prob. 9.60PCh. 9 - Prob. 9.61PCh. 9 - Prob. 9.63PCh. 9 - Prob. 9.64PCh. 9 - Common practice in chemical processing plants is...Ch. 9 - Consider the electrical heater of Problem 7.49. If...Ch. 9 - Prob. 9.67PCh. 9 - A billet of stainless steel, AISI 316, with a...Ch. 9 - Lone stainless steel rods of 50-mm diameter are...Ch. 9 - Hot air flows from a furnace through a...Ch. 9 - A biological fluid moves at a flow rate of...Ch. 9 - A sphere of 25-mm diameter contains an embedded...Ch. 9 - Prob. 9.79PCh. 9 - A vertical array of circuit boards is immersed in...Ch. 9 - Prob. 9.81PCh. 9 - The front door of a dishwasher of width 580 mm has...Ch. 9 - A natural convection air healer consists of an...Ch. 9 - A bank of drying ovens is mounted on a rack in a...Ch. 9 - Prob. 9.85PCh. 9 - Prob. 9.86PCh. 9 - Prob. 9.87PCh. 9 - To reduce heat losses, a horizontal rectangular...Ch. 9 - Prob. 9.89PCh. 9 - Prob. 9.90PCh. 9 - Prob. 9.91PCh. 9 - Prob. 9.92PCh. 9 - A 50-mm-thick air gap separates two horizontal...Ch. 9 - Prob. 9.94PCh. 9 - A vertical, double-pane window, which is 1 m on a...Ch. 9 - The top surface (0.5m0.5m) of an oven is 60°C for...Ch. 9 - Prob. 9.97PCh. 9 - Prob. 9.98PCh. 9 - Consider the cylindrical. 0.12-m-diamter radiation...Ch. 9 - Prob. 9.100PCh. 9 - A solar collector design consists of an inner tube...Ch. 9 - Prob. 9.104PCh. 9 - Prob. 9.105PCh. 9 - Liquid nitrogen is stored in a thin-walled...Ch. 9 - Prob. 9.108PCh. 9 - Prob. 9.109PCh. 9 - Prob. 9.110PCh. 9 - Prob. 9.111PCh. 9 - Prob. 9.114PCh. 9 - Prob. 9.115PCh. 9 - Prob. 9.116PCh. 9 - Prob. 9.117PCh. 9 - A water bath is used to maintain canisters...Ch. 9 - On a very Still morning, the surface temperature...Ch. 9 - Fuel cells similar to the PEM cell of Example 1.5...
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.Similar questions
- The objectives of this experimentarrow_forward2. Losses by Natural Convection from diameter and 121.9 mm Cylinder. A vertical cylinder 76.2 mm in high is maintained at 397.1 K at its surface. It loses heat by natural convection to air at 294.3 K. Heat is lost from the cylindrical side and the flat circular end at the top. Calculate the heat loss, neglecting radiation losses. Use the simplified equations of Table 15.5-2 and those equations for the lowest range of NGr Npr. The equivalent L to use for the top flat surface is 0.9 times the diameter. Ans. q 26.0 W a 11arrow_forwardi need the answer quicklyarrow_forward
- (B) Stainless steel tube is used to transport pharmaceutical liquids, it has an inner diameter of 40 mm and a wall thickness of 4 mm. The pharmaceutical and ambient air are at temperatures of 6 C and 23C, respectively, while the corresponding inner and outer convection coefficients are 400 W/m² .K and 6 W/m² K, respectively. (a) What is the heat gain per unit length? (b) What is the heat gain per unit length if a 10 mm thickness layer of calcium silicate insulation (kins = 0.050 W/m. K) is applied to the tube? Page 5 of 8 l ri = 20mm 2=22mm Toi=60 hi-400w/m²k insulation kin=0.05w/mk Too,o=23°C ho=6W/m²karrow_forwardI REALLY NEED THE ANSWER UNTIL 5:20PM PLEASE A vertical cylindrical container is being cooled in ambient air at 25°C with no air circulation.If the initial temperature of the container surface is 100°C, compute the surfaceheat transfer coefficient due to natural convection during the initial cooling period. Thediameter of the container is 1 m, and it is 2m high. HELP ME IF MY SOLUTION IS CORRECT, I THINK THIS IS NOT COMPLETE YET. KINDLY HELP ME PLEASEarrow_forwardTransport Phenomena Questionarrow_forward
- A thermal energy storage unit consists of a large rectangular channel, which is well insulated on its outer surface and encloses alternating layers of the storage material and the flow passage. Storage material Each layer of the storage material is an aluminum slab which is at an initial temperature of 25 °c. The characteristic length is equal to 0.025 m. Consider conditions for which the storage unit is charged by passing a hot gas through the passages, with the gas temperature and the convection coefficient assumed to have constant values of T= 600 °C and h=100 W/m.K throughout the channel. k= 231 W/m. K, c=1033 J/kg. K, p = 2702 kg/m' a) How long will it take to achieve 75% of the maximum possible energy storage? b) What is the temperature of the aluminum at this time?arrow_forward4. An electrical heater in the form of a horizontal disk of 400-mm diameter is used to heat the bottom of a tank filled with engine oil at a temperature of 5°C. Calculate the power required to maintain the heater surface temperature at 70°C. tal uninsulated steam pipe passes throu pipe ofarrow_forwardipe 1 ft (0.3048 m) in diameter is maintained at a temperature of 250°C in a room ent air is at 15°C. Calculate the free-convection heat loss per meter of length.arrow_forward
- (B) A vertical cylinder 1.5m height and 18 cm in diameter is maintained at 100°C in an atmosphere environment of 20°C. Calculate the heat loss by free convection from the surface of the cylinder. Use the following data: p=1.06 kg/m v =18.97×10“ m²/s, k=0.1042 W/mK and Pr=0.6975 Nu =0.1 (Ra)'3arrow_forwardDon’t use Heissler charts to answer this question Heat sterilization of lumber, timbers, and pallets is used to kill insects to prevent their transfer between countries in international trade. This is analogous to food sterilization by heat. A typical requirement here is that the slowest heating point of any woodconfiguration be held at 56 °C for 30 minutes. Consider hot air heating of wooden boards that maintains their surface temperature at 70 °C. The boards are stacked outside and in the winter time they can be considered to be at 0 °Cwhen theyare brought in for heating. The thermal diffusivity of the wood is 9*10-8m2/s. a.Calculate the time from the start of heating for a 2.5 cm thick board to reach a sterilization temperature of 56 °C at its slowest heating point .b.Calculate the heating time when four such boards are stacked together. c.Calculate the ratio of the two heating times (for a single board versus when they are stacked), and explain the ratio. Note: You’re free to…arrow_forwardbe 1 ft (0.3048 m) in diameter is maintained at a temperature of 250°C in a room ent air is at 15°C. Calculate the free-convection heat loss per meter of length.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author: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
Heat Transfer – Conduction, Convection and Radiation; Author: NG Science;https://www.youtube.com/watch?v=Me60Ti0E_rY;License: Standard youtube license