Problem 3 (25 points) In an experiment to find the convective heat transfer coefficient, an internally...
heat and mass transfer
(20 points) Air at 25°C cools a 2170 cylindrical battery (with a diameter of 21 mm and a length of 70 mm) with a cross flow velocity of 6 m/s. a) Determine the average convective heat transfer coefficient. (b) If the battery's internal heat generation is 5W and its thermal conductivity is 0.6 w/m-k, the determine the battery surface temperature and the maximum temperature in battery
(20 points) Air at 25°C cools a 2170 cylindrical battery...
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A heat-transfer experiment in CBE 154 investigates conductive heat transport within a solid and convective heat transport at a solid gas interface. In this homework problem, you are to write the differential equations describing the experimental setup (but not solve them). The first part of the experiment involves measurement of a steady-state temperature profile along a brass rod to determine the conductivity of brass and the rate of heat loss through the insulation to the surrounding...
Page 2 of 3 Part II-Trivia (40%): check more than one if applicable Convective heat transfer at a surface is affected by the air speed. Which of the following statements is true () Increasing the air speed increases convective heat transfer () the thickness of the air film (coefficient) increases with air speed a) ) the air film (coefficient) is like an insulating blanket over the surface () the air film (coefficient) offers resistance against heat transfer The Reynolds number...
6 Water is heated in a pipe by exchanging heat with a warmer fluid that flows outside the pipe. Inside diameter of the pipe is dn 0.045 m and outside diameter dour0.05 m. Mean velocity of the water in the pipe is um-0.31 m/s and the bulk temperature is 323 K (density 988 kg m-3; viscosity 0.00055 kg m' sı. Pr 3.56, thermal conductivity k 0.64 W m1 Kt). The material of the pipe has thermal conductivity k 0.61 W...
Problem 1 (25 points) In an experiment to measure heat transfer coefficients, a very thin foil of low emissivi attached to a slab of material with low thermal conductivity. The other surface of the metal foil is exposed to convection heat transfer by fluid flowing over the foil surface. The slab on which the metal foil is attached has a thickness of 30 mm and a thermal conductivity of 0.023 W/m K in a condition where the surrounding room temperature...
A counter-flow heat exchanger is stated to have an overall heat transfer coefficient of 284 W/m2.K when operating at design and clean conditions. Hot fluid enters the tube side at 101°C and exits at 71°C, while cold fluid enters the shell side at 27°C and exits at 42°C. After a period of use, built-up scale in the heat exchanger gives a fouling factor of 0.0004 m2 K/W. The surface area is 93 m². Assume both hot and cold fluids have...
Problem 3 (20 points) A cross-flow heat exchanger consists of a bundle of 32 tubes in a long duct. Hot water at 150°C and a mean velocity of 0.5 m/s enters the tubes having inner and outer diameters of 10.2mm and 12.5mm and has to be cooled to 136°C. The tubes are made of steel of thermal conductivity k-40 W/m.K. Air at 10°c enters the exchanger (unfinned) with a volumetric flow rate of 1.0 m3/s. The convective heat transfer coefficient...
Problem 2: Heat exchanger (25 points) Cold water (op 4179 J/kg K) enters the tubes of a heat exchanger at 20 °C at a rate of 3 kgs. while hot oil (cp 2200 J/kg.K) enters the shell at 130 C at the same mass flow rate and leaves at 60°C The heat exchanger consistsoftwo shells and 20 tubes, each executing four passes (two passes per shell). If the W/m2-K, assume the tube wall is very thin with convective heat transfer...
summatize the following info and break them into differeng key points. write them in yojr own words
apartus
6.1 Introduction—The design of a successful hot box appa- ratus is influenced by many factors. Before beginning the design of an apparatus meeting this standard, the designer shall review the discussion on the limitations and accuracy, Section 13, discussions of the energy flows in a hot box, Annex A2, the metering box wall loss flow, Annex A3, and flanking loss, Annex...
summarizr the followung info and write them in your own words and break them into different key points. 6.5 Metering Chamber: 6.5.1 The minimum size of the metering box is governed by the metering area required to obtain a representative test area for the specimen (see 7.2) and for maintenance of reasonable test accuracy. For example, for specimens incorporating air spaces or stud spaces, the metering area shall span an integral number of spaces (see 5.5). The depth of...