Heat Transfer 1 Problem 1 During a cold winter day, wind at 55 km/h is blowing...
Assume constant acceleration, During a winter day, wind at 58 km/h, 5°C, and 1 atm is blowing parallel to a 3.5-m-high and 9-m-long wall of a house. Approximating the wall surfaces as smooth, determine the friction drag acting on the wall. What would your answer be if the wind velocity has doubled? How realistic is it to treat the flow over side wall surfaces as flow over a flat plate?
Wind is blowing at 5 km/h over a building wall of size 5 mx10 m. Air temperature is 0°C and wall 1) surface is at 10°C. 1) Calculate the avg. heat transfer coefficient along the 10 m width of the wall. 2) Calculate the local heat transfer coefficient at a location 10 cm from the leading edge of the wall. (25pts) Wind is blowing at 5 km/h over a building wall of size 5 mx10 m. Air temperature is 0°C...
Question 1: Identify the classification of the following heat transfer (convective flow) problems: *Note that there may be other modes of heat transfer present (e.g. radiation or conduction), but ignore those effects. For example, a hot ball bearing being dropped from a building roof. Ans. Forced, external convection over a sphere. a. Water flow through a fire hose from a hydrant. b. Heat transfer from a clothes iron sitting on an ironing board. c. Heat transfer from a climber trapped...
A 0.1 m thick brick wall with thermal conductivity 0.66 Wm K-1 is exposed to cold wind on the outside of a house, at 270 K with convective heat transfer coefficient of 22.43 Wm2K1. On the inside of the house is calm air at 295.8 K, with a natural convective heat transfer coefficient of 10.49 Calculate the rate of heat transfer per unit area, in Wm, giving your answer to 3 decimal places A 0.1 m thick brick wall with...
Could someone help me by answering all of this questions from Q7) A to D and Q8) A to C. Thank You Q.C7 An 80 kg cyclist is riding her 15 kg bicycle down a hill with a slope of 12 degrees without pedalling or braking. The cyclist has a frontal area of 0.45 m and a drag coefficient of 1.1 in the upright position. Taking air density to be 1.25 kg/m2, and neglecting bearing friction and rolling resistance (a)...
On a cold winter day where the outside temperature is -10o C, a heat pump provides 20 kW to heat a house to 20o C. The heat pump has a COPHP of 4 at the maximum power. The next day a storm brings the outside temperature down to −15o C. If the ratio of COPHP and the reversible COPrev for day 1 and day 2 is the same, COPHP for both days is the same, and that the house loses...
In this problem you will estimate the heat lost by a typical house, assuming that the temperature inside is T(in) = 20 degrees celcius and the temperature outside is T(out) = 0 degrees celcius. The walls have fiberglass insulation, which dominates the heat conduction properties of the wall So we can consider the wall to have a thermal conductivity of k(wall) = 0.048 W/m/K . We will take the thickness of the walls and ceiling to be L(wall) = 12...
Solve the following problem using theories from heat transfer. On a cold winter day, the inside of a window of a heated building is colder than the inside surrounding air. Natural convection results from this temperature difference. (a) Imagine this window as a vertical surface where T; < Ta, sketch the resulting boundary layer that forms. Also sketch the velocity profile of the air through the boundary layer. (b) What are the key differences between the velocities in this boundary...
Heat Transfer Problems 1. A window pane (1/8 inch thick) in an old house owned by a professor is 3 ft. by 4 ft. He likes to be warm in the winter so the inside temperature is kept at 70 °F even when the outside temperature is 10 •F. For this problem assume the inside and outside temperatures are for the window surface. How much heat is transferred through the window (k=.54 BTU/hr ft ° F)? 2. A small heated...
During a big storm a 60 km/h wind blows across the surface of a 2.00 m times 1.00 m window. What is the force on the window associated with this wind? The density of the air is 1.20 kg/m^3. A) 333 N pointed toward the inside the house. B) 333 N pointed toward the outside of the house. C) 3000 N pointed toward the inside of the house. D) 3000 N pointed toward the outside of the house F) 0...