Cooling Tower For An Internal Combustion Enginet 5 Engineers An Internal Combustion Engine Is Set Up In A Laboratory 1 (46.29 KiB) Viewed 31 times
Cooling Tower for an Internal Combustion Enginet (5 engineers) An internal combustion engine is set up in a laboratory, and it is necessary during operation of the engine to reject heat to the environment. A common radiator (a cross-flow heat exchanger) is part of the system, and it will reject heat to the air. The power developed by the engine is absorbed by a water brake dynamometer (similar to a pump), in which water is moved under pressure through an elaborate system of vanes, pipes, and valves. The water will gain energy in the form of heat, and this heat must be rejected safely to the environment. It is proposed to reject this heat by means of a cooling tower. A cooling tower will cool the water to near-ambient temperature. As indicated in Figure 11.11, a cooling tower is an evaporative cooler that causes the evaporation of a small portion of the water to transfer heat from the system. Cooling towers can be small rooftop units or very large structures Cooling towers can be classifed in a number of ways: according to size, or according to how air is made to flow through the system duty, or how the air and water flow paths align with respect to each other. Wet cooling towers transfer heat to the surrounding air by the evaporation of a small fraction of the water flowing through. Dry cooling towers contain a heat exchanger in which the water and air are kept separate. Heat is transferred through the exchanger surfaces. In a natural draft cooling tower, a tall chimney is used to enhance the movement of a warmed current of air. The air moves due to buoyant effects, as opposed to that in a mechanical draft tower where the air is moved by a fan.
moist air flow out fan warm water inlet sprayers counterflow air flow inlet air flow inlet cool water out FIGURE 11.11. Sketch of a cooling tower. To be designed, selected, or determined: 1. Prepare a written description for the nontechnical reader of how a wet cooling tower works. 2. What is "splash fill"? 3. What possible malfunctions are encountered if a cooling tower is used during cold weather? What safety concerns exist where cooling towers are used? 4. Design a mechanical draft, counterflow cooling tower to discharge heat from an internal combustion engine test stand to the environment. The engine specifications will be provided by the instructor. 5. Use commonly available materials wherever possible. 6. Determine the cost of such a device. 7. Is a pump necessary to move the water through the tower? What is the flow rate of the water? 8. Is a fan necessary to move air through the tower? What is the flow rate of the air? Submitted by Professor John I. Hochstein.
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