Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN: 9781305387102
Author: Kreith, Frank; Manglik, Raj M.
Publisher: Cengage Learning
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Chapter 3, Problem 3.7P
To determine
The soaking annealing time required and drawing velocity of the wire:
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In a metal wire manufacturing facility, continuously drawn copper wire with a 2.5 mm diameter is annealed by heating it from its initial temperature of 450C to 400oC in a soaking oven. The oven inside air temperature is 7000C with an average heat transfer coefficient of hc =45 W/(m2 K). Estimate the soaking annealing time required. Also if the oven is 3.5 m long and the drawn wire is continuously fed through the oven (entering at one end and pulled out at the other longitudinal end), what should be the drawing speed or velocity?
Quenching is a rapid cooling process by which many metallic alloys are hardened. Brass (a copper alloy: 70 Cu, 30 Zn) plates that are 4 mm thick are quenched in a water bath at a heat treating plant. If a brass plate is initially at 4500C determine the quench time needed for the plate to attain 900C. The water bath temperature is 800C and has an average convective heat transfer coefficient of 45 W/(m2 K), determine how long the plate has to remain in the oven.
2 (a) A short bronze cylinder of diameter 6 cm and length 12 cm is initially at 40°C and
then plunged into a fluid at 200°C. The temperature at the centre of the cylinder is
measured by a thermocouple to be 150°C after 5 minutes. What is the convective heat
transfer coefficient between the cylinder and the fluid?
The following properties of the bronze cylinder may be used:
Thermal conductivity k = 26 W/m-K, density p = 8800 kg/m², and specific heat c =
420 J/kg-K. State and justify all assumptions made.
Chapter 3 Solutions
Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
Ch. 3 - Consider a flat plate or a plane wall with a...Ch. 3 - 3.2 High-strength steel is required for use in...Ch. 3 - Prob. 3.3PCh. 3 - 3.5 In a ball-bearing production facility, steel...Ch. 3 - A 0.6-cm diameter mild steel rod at 38C is...Ch. 3 - Prob. 3.7PCh. 3 - Prob. 3.8PCh. 3 - 3.9 The heat transfer coefficients for the flow of...Ch. 3 - 3.10 A spherical shell satellite (3-m-OD,...Ch. 3 - Prob. 3.11P
Ch. 3 - Prob. 3.12PCh. 3 - Prob. 3.13PCh. 3 - 3.14 A thin-wall cylindrical vessel (1 m in...Ch. 3 - A thin-wall jacketed tank heated by condensing...Ch. 3 - 3.16 A large, 2.54-cm.-thick copper plate is...Ch. 3 - 3.17 A 1.4-kg aluminum household iron has a 500-W...Ch. 3 -
3.28 A long wooden rod at with a 2.5-cm-OD is...Ch. 3 - A mild-steel cylindrical billet 25 cm in diameter...Ch. 3 - Prob. 3.37PCh. 3 -
3.38 An egg, which for the purposes of this...
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- Please answer the given question and show the solution. Thank you very much! Note: Please include the units in the solution and use 4 decimals point in Final Answer.arrow_forwardProblem #2: A mass of ice at -4°C is needed to cool 115 kg of vegetables in a bunker for 24 hours. The initial temperature of the vegetables is assumed to be 29°C. It is also assumed that, within the 24-hr period, the average temperature inside the bunker is 7°C. If the heat gained per hour in the bunker is 30% of the heat removed to cool the vegetables from 29°C to 7°C, what would be the required mass of ice in kg? Use: Specific heat of water 4.2292 kJ/kg-°C • Specific heat of ice 1.9387 kJ/kg-°C Specific heat of vegetables 3.35 kJ/kg-°Carrow_forwardExample: 0.5 kg of water per minute is heated from 20° to 40°C when passed through a tube of 2.5 cm diameter steel pipe. The pipe surface temperature is maintained at 110°C by condensing steam on its surface. Find out the length of the pipe required. The properties of water at mean temperature of 70°C are given below: p = 978 kg/m² k= 0.575 W/m. K Cp = 4200 J/kg. K v = 0.415 x 10-6 m²/secarrow_forward
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