Consider a person who is trying to keep cool on a hot summer day by turning a fan on and exposing his entire body to air flow. The air temperature is 85°F and the fan is blowing air at a velocity of 6 ft/s. If the person is doing light work and generating sensible heat at a rate of 300 Btu/h, determine the average temperature of the outer surface (skin or clothing) of the person. The average human body can be treated as a 1-ft-diameter cylinder with an exposed surface area of 18 ft2. Disregard any heat transfer by radiation. What would your answer be if the air velocity were doubled? Evaluate the air properties at 100°F.

Q: Consider a person standing in a room maintained at 20°C at all times. The inner surfaces of the…

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Q: How does transient heat transfer differ from steady heat transfer? How does one-dimensional heat…

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Q: The outer wall consists of a 30 cm thick brick wall which is covered by a layer of styrofoam. How…

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Q: A 10 cm diameter aluminum ball is to be heated from 94°C to an average temperature of 140°C in 30…

A: Given that ,  Diameter D=10cm Radius r=5cm T1=94°CT2=140°Ct=30min=30×60s=1800sCp=0.91kJ/kgK

Q: etermine the surface tem

A: Given: Q=0.4 W d=0.3 cm L=1.8 cm v=240 m/min air temp=35oC To determine: Surface temperature

Q: Consider a 0.6-m-high and 1.2-m-wide double-pane 0.78 W/m-K) separated by a 8-mm-wide stagnant a…

A: Given data  Thickness of glass = 3mm Conductivity of glass = 0.78(W/m-k) Thickness of air gap = 8mm…

Q: A Ball is heated to a temperature of 100°F throughout and is allowed to cool in ambient air at Temp…

A: When a temperature gradient exits perpendicular to the area, thermal conductivity is defined as the…

Q: The inside and outside surfaces of a 1-cm thick, 4-m squared-shaped

A: Given data⇒ Thickness (t)=1 cm=0.01 m Side of square(a)=4 m Inside temperature T1=90C=9+273T1=282 K…

Q: Two friends, Jack and Jill, sit down to talk and enjoy a cup of coffee. When the coffee is served,…

A: For the given situation  Jack add cream immediately Jill add cream after 10 mins   Assumption  cream…

Q: What is the heat power lost from the cup to the air due to convection? Take the external surface of…

A: Given :  The convection heat transfer coefficient h=7.10 Wm2K Cup and liquid radius  r=4 cm =0.04 m…

Q: What is the ton of refrigeration required to cool 15,000 lbm of fresh pork from a temperature of…

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Q: Under conditions for which the same room temperature is maintained by a heating or cooling system,…

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Q: The net radiant-heat exchange between a 20-by-20 ft rough plaster panel-heated ceiling and a…

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Q: Rock has often been suggested as a medium for the thermal storage of energy. A cylindrical piece of…

A: “Since you have posted a question with multiple sub-parts, we will solve first three subparts for…

Q: Consider water (at a temperature of 276 K ) flowing inside a cylindrical pipe, having a diameter of…

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Q: The space in a small building with average construction quality is to be provided with ventilation…

A: Write the expression of number of air changes per hour.

Q: Consider a person standing in a roomn at 20°C with an exposed surface area of 1.5 m2. The deep body…

A: Given Data: Deep body temperature, T1=37 C The thickness of the skin, x=0.5 cm Thermal conductivity…

Q: Hot air at 79.0 oC is blown over a 3-m by 5-m flat surface at 34.9 oC. If the average convection…

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Q: A person extends her arm in a manner shown into the windy air outside the shrine. The is 53F and…

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Q: Answer shows Qtotal and Temperature at inner surface of window. 496W, 0.4°C Ob, 542W, 1.2°C O. 572W,…

A: Solution : Given data : Height (h)= 1.0 m                     Width (b)= 1.75 m…

Q: eat-transfer rate through the wall is q = (T1 - T2) / (1/h1A + x/kA + 1/h2A) where T1 and T2 are…

A: Given    Temperature inside the wall = T1  Temperature outside the wall = T2               Thermal…

Q: Two friends, Jack and Jill, sit down to talk and enjoy a cup of coffee. When the coffee is served,…

A: Let us assume that Cream is cooler than the room temperature, jill takes the hotter coffee. Newton's…

Q: A 3.0m-long, 0.45-cm-diameter electrical wire extends across a room at 61°F, as shown. Heat is…

A: Given data: L=3 md=0.45 cmT1=61°F=289.26 KT2=306°F=425.37 KV=70 VI=1.73 A Need to determine the heat…

Q: How does the science of heat transfer differ from the science of thermodynamics? Give your answers…

A: Thermodynamics and Heat Transfer both are part of thermal engineering and each has its own meaning…

Q: A cylindrical rod with a diameter of 20 mm and a length of 300 mm is heated to a temperature of…

A: Write the given data. Diameter, d=20 mm=0.02 mLenght, l=300 mm=0.3 mInitial temperature of rod,…

Q: A thin metal plate is insulated on the back and exposed to solar radiation on the front surface. The…

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Q: There is a cylindical piece of nickel, that is 5 cm in diameter and 10 cm in length, that is…

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Q: In a concentrated solar power plant, molten salt tank is used to store the thermal energy from the…

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Q: Required information Consider an electrically heated brick house (k = 0.40 Btu/h-ft-°F) whose walls…

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Q: determine the rate of flow through the boiler

A: Given data; L1=20×10-3 mk1=58 W/m0cL2=5×10-3mk2=0.116 W/m0cT1=3000CT2=500C Therefore find rate of…

Q: Consider a 1.5-m-high and 2.4-m-wide double-pane window consisting of two 3-mm-thick layers of glass…

A: In this problem, we will calculate the steady rate of heat transfer and the inner surface…

Q: An average person body surface is approximately 2.0 m². Its skin temperature is 33°C. The convection…

A: Find convective heat transfer .

Q: A 2-m2 window has a surface temperature of 15°C, and the outside wind is blowing air at 2° C across…

A: Data given-  A = 2 m2  Tsurface = 15°C  Tair = 2°C  h = 125 W/m2 K

Q: (b) Consider a person standing in a room maintained at 25°C at all times. The inner surfaces of the…

A: Given datafor winterTsur=15°Cfor summerTsurr=28°CA=1.5m2Ts=30°Cε=0.95

Q: The top surface of the passenger car of a train moving at a velocity of 115 km/h is 2.8 m wide and 8…

A: To find : The equilibrium temperature of the top surface of the car . Given: The velocity of train…

Q: Determine the heat transfer rate by convection from an electronic chip whosesurface temperature is…

A: The mode by which heat is transferred between a solid surface and the adjacent fluid in motion when…

Mechanisms of heat transfer

Heat transfer is an essential discipline in thermal engineering that deals with the transfer, conversion, usability, and creation of heat or thermal energy. Transfer of heat occurs through various mechanisms like conduction, convection, radiation, and change of phases. All these mechanisms have distinct characteristics, but these mechanisms can simultaneously occur in an identical system.