Chapter 1, Problem 1.68P

The fan circulates the warm air on the inside of the windshield to stop condensation of water vapor and allow for maximum visibility during wintertime (see images). You have been provided with some info. and are asked to pick from the bottom table, the right model number(s) that will satisfy the requirement.Your car is equipped with a fan blower setting that allow you to choose between speeds 0, 1, 2 and 3. Variation of the convection heat transfer coefficient is dependent upon multiple factors, including the size and theblower configuration.following image shows the parameters

2. A steam line is covered with two successive layers of insulation. The 1.6 in thick layer in contact with the pipe is asbestos which is covered with a 1.4 inch thickness of magnesia insulation. The internal pipe diameter is 3 in, the pipewall thickness is 0.40 in made from common brick. The steam temperature is 850ºF, and the internal surface film coefficient is 50 Btu/hr.ft².F, while the ambient outer temperature is 105°F and the outer surface film coefficient is 3.0 Btu/hr.ft².F. Calculate the following: a. value of U based upon the external area of the magnesia covering, Btu/hr.ft2.F b. heat loss from the steam for a length of 190 feet of pipe, Btu/hr

An underwater sonar that maps the ocean bathymetry is encapsulated in a sphere with a diameter of 85 mm. During operation, the sonar generates heat at a rate of 300W. What is the sonar surface temperature when it’s located in a water column where the temperature is 15o C and the water current is 1 m/sec? The sonar was pulled out of the water without turning it off, thus, it was still working. The air temperature was 15o C and the air speed was 3 m/sec. What was the sonar surface temperature? Was there any reason for concern?

A spherical interplanetary probe of 0.5-m diameter contains electronics that dissipate 150 W. If the probe surface has an emissivity of 0.8 and the probe does not receive radiation from other surfaces, as, for example, from the sun, what is its surface temperature?

Let's say a 3.0 gram copper wafer is dropped from a height of 50.0 meters. If 60% of the potential energy lost in the drop could be converted to thermal energy used to heat the copper from an initial temperature of 25 degrees celsius, what would the final temperature of the copper wafer? Would the answer be different if the wafer has a mass greater than 3 grams? Note: the specific heat of copper is 387 J/(kg*K). The temperature is between 25.8 and 26.0 degrees celsius, yes the bigger the mass the greater the energy. O The temperature is between 25.6 and 25.8 celsius, answer does not depend on mass. O The temperature is between 25.0 and 25.2 celsius, answer does not depend on mass. O The temperature is 25.5 and of course the more mass something has the greater energy will be needed to raise the temperature. The temperature is 26.2 and if the mass is doubled so will be the change in temperature. O The temperature is 25.9 degrees celsius and the answer does not depend on mass. O The…

A camera used for monitoring marine life is placed in water where T.. -5°C and the convection heat transfer coefficient h=1420 W/m²K. The camera is operating, but its battery is experiencing thermal runaway, causing the camera to become very hot, and there is volumetric heat generation, qe inside it. There is no heat generation within the waterproof, protective enclosure surrounding it. 00:08 The camera is already compromised; however, its owner hopes to save the protective case. Each interface (between layers A and B and between layers B and C) must not exceed a temperature of 185°C, or these plastic, protective layers will begin to melt. Approximate the camera and its casing as a composite, rectangular object with flat surfaces. The device's total thickness, L=LA + 2LB +Lc, is much smaller than its area (into the page); therefore, 1-D conduction can be approximated through the layers. On the left surface of layer A, the temperature is measured to be T₁ = 8.0°C, and the temperature on…

A radiator plate of 0.2-m (wide) x 0.4-m (height) is in a room of 22°C. One side (the hot side facing the room) of the radiator plate is maintained at a temperature of 80°C, the other sides are assumed to be insulated, as shown in Figure 1. If the following assumptions can be made: 1) steady operating conditions exist; 2) the air an ideal gas; 3) the local' atmospheric pressure is 1.00 atm: (a) Briefly and qualitatively analyze the four different locations for the radiators marked A), B), C) and D), as shown in Figure 1, and rank them in terms of heat transfer efficiency by natural convection. (b) Determine the rate of heat transfer from the radiator plate by natural convection if the plate is A) vertical and C) horizontal with the hot surface facing down. Compare the two and provide a brief discussion of the findings. wall A 0.4 mi C 0.4 m 0.4 m B floor ceiling 0.4 m wall Nu Nu=0.59Ra Nu-0.1 Raa 0.387Ral Nu- - {0.825 + 11 + (0.492/Pr)162) (complex but more accurate) Use vertical plate…

1-Y Cpt 1 = (1+y)(1+ a + 5) (16+06+ €2²) f= fp+afe 2Lp

We wish to use the analytical model developed by Joshi and Webb to predict the heat transfer and friction characteristics (j and f) of the Offset Strip-Fin (OSF) array. 1. Compare the predictions of the friction factor using equation 5.6 of the book to the measurements of Webb and Joshi (taken from "Prediction of the Friction Factor for the Offset Strip-Fin Matrix" and given in the last column of the table below) for surfaces 1 and 8 (see Table below) at Reph = 529 and 623, respectively. As shown in the table below, the experimental friction factors for surfaces, 1 and 8 are 0.0551 and 0.0434 respectively. Use CD = 0.8. Surface 1 8 α 0.123 0.224 t/l 0.016 0.064 h (mm) 38.1 38.1 t (mm) Dh (mm) 7.518 0.406 1.626 10.897 0.0551 0.0434 2. Use the Webb and Joshi model given in the notes to make a plot of Nu versus the fin length (1) for 1 mm < 1<5 mm. You should use 0.5 mm increments of 1 or smaller. Use α= 0.184, t = 0.102 mm, h = 4.98 mm, and Reph = 500. Explain why the Nu behaves as it…