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 9.34P
(a)
To determine
The power removed by the free convection and radiation from the lateral and the upper horizontal surface.
(b)
To determine
The heat removal rate by free convection.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
(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/m² v=18.97×106 m²/s, k=0.1042 W/mK and Pr=0.6975
1/3
Nu =0.1 (Ra)¹/
A school classroom is 6 m long, 6 m wide and 3 m high. There is a 2.5 m x 4 m window in the east wall. Only the east wall/window is exterior. Assume the thermal conditions in adjacent spaces (west, south, north, above and below) are the same as those of the classroom. Determine the cooling load at 9:00 am, 12:00 noon on July 21.
Other known conditions include:
Latitude = 40o N
Ground reflectance = 0.2
Clear sky with a clearness number = 1.0
Overall window heat transmission coefficient = 7.0 W/m2.K Room dry-bulb temperature = 25.5°C
Permissible temperature exceeded = 2.5% Schedule of occupancy: 20 people enter at 8:00 am and stay for 8 hours Lighting schedule: 300 W on at 8:00 AM for 8 hours
Exterior wall structure:
• Outside surface, A0
• Face brick (100 mm), A2
• Insulation (50 mm), B3
• Concrete block (100 mm), C3 • Inside surface, E0
Exterior window:
• Single glazing, 3 mm
• No exterior shading, SC = 1.0
A common arrangement for heating a large surface area is to move warm air through rectangular ducts below the surface. The ducts are square and located midway between the top and bottom surfaces that are exposed to room air and insulated, respectively. For the condition when the floor and duct temperatures are 30C and 80C, respectively, and the thermal conductivity of concrete is 1.4 W/m*K, calculate the heat rate from each duct, per unit length of the duct. Use a grid spacing with delta x = 2*(delta y), where delta y = 0.125L and L=150mm.
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
- ASAParrow_forwardUnique characteristics of biologically active materials such as fruits, vegetables, and other products require special care in handling. Following harvest and separation from producing plants, glucose is catabolized to produce carbon dioxide, water vapor, and heat, with attendant internal energy generation. Consider a single apple, spherical in shape, diameter 80 mm, which is ventilated with air at 5°C and h= 7.5 W/m2.K. Within the apple thermal energy is uniformly generated at 4000.0J/kg.day. The density and thermal conductivity of the apple are 840 kg/m3 and 0.5 W/m.K. a. Derive an equation for temperature distribution inside the apple. Use the boundary conditions @r R, T = Ts, and @r=0, dT/dr 0. Ts is the surface temperature of sphere to be determined using convection equation. b. Determine the apple center and surface temperatures.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_forward
- A house with a flat horizontal roof has a black tar waterproof finish. the underside of the roof is well insulated. The upper surface is exposed to ambient air at 298 K. The convection heat transfer coefficient is 11W/m2K. Calculate the average equilibrium temperature of the roof for the following conditions; (i) Clear sunny day with incident solar radiation flux of 500W/m2arrow_forwardasaparrow_forwardA 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/m³ v= 18.97x106 m²/s, k-0.1042 W/mK and Pr=0.6975 Nu =0.1 (Ra)¹/3arrow_forward
- question in image need help with part c onlyarrow_forwardA 212-mm-square, 15-mm-thick tile has the thermo-physical properties of Pyrex (ϵ = 0.83) and emerges from a curing process at an initial temperature of Ti = 145°C. The backside of the tile is insulated while the upper surface is exposed to ambient air and surroundings at 25°C. (a) Estimate the time required for the tile to cool to a final, safe-to-touch temperature of Tf = 42°C. Use an average tile surface temperature of T¯=(Ti+Tf)/2 to estimate the average free convection coefficient and the linearized radiation coefficient. How sensitive is your estimate to the assumed value for T¯? (b) Estimate the required cooling time if ambient air is blown in parallel flow over the tile with a velocity of 10 m/sarrow_forwardQuestion No. 1 Gaseous carbon dioxide at 1 atm and 300°C is flowing inside a horizontal pipe that has 5.3 cm ID and 6.0 cm OD. The flow velocity of carbon dioxide is 15 m/s. The outside surface of the pipe is exposed to the atmospheric air that has temperature of 40°C. Considering free convection conditions at the outer pipe surface and assuming pipe wall temperature as 200°C, calculate the inside overall heat transfer coefficient, outside heat transfer coefficient, and overall heat transfer coefficient based on the inside surface of the pipe. Warning: Calculate both the inside and the outside heat transfer coefficients only using the respective correlations and ignore radiation effects.arrow_forward
- 3. Consider a 3 m high rectangular enclosure consisting of two surfaces separated by a 0.1 m air gap at 1 atm. If the surface temperatures across the air gap are 30 °C and -10 °C, determine the ratio of the heat transfer rate for the horizontal orientation (with hotter surface at the bottom) to that for vertical orientation. [1.66] 0.1 m 3 m Air -10°C -10°C 30°C Air 30°℃ > 3marrow_forward(a) If the cost of producing the hot water is $0.10 per kWh, what is the representative daily costof heat loss from an uninsulated pipe to the air per meter of pipe length? The convectionresistance associated with water flow in the pipe may be neglected.(b) Determine the savings associated with application of a 10-mm-thick coating of urethaneinsulation (k = 0.026 W/m-K) to the outer surface of the pipe.arrow_forwardAn overhead 25-m-long, uninsulated industrial steam pipe of 162-mm diameter is routed through a building whose walls and air are at 25°C. Pressurized steam maintains a pipe surface temperature of 150°C, and the coefficient associated with natural convection is h = 10 W/m².K. The surface emissivity is ε = 0.8. (a) What is the rate of heat loss from the steam line? (b) If the steam is generated in a gas-fired boiler operating at an efficiency of MJ, what is the annual cost of heat loss from the line? = 0.90 and natural gas is priced at Cg = $0.02 perarrow_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