Quote:
Originally posted by Miss Tree
Maybe FIRSTies will be honored with a public demonstration of the new Stirling engine.
If so, it might be more interesting for you all if you read up on Boyle's law.
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Boyle's law works! If you have ever had any doubt, try this simple test:
- step 1: while standing at approximately sea level, measure the circumference of your waist
- step 2: eat a big plate of baked beans
- step 3: board any commercial airliner
- step 4: measure your waist again
- step 5: apologize to your fellow passengers, and note that the entire air volume of the aircraft should be exhausted and replaced within 30 minutes, and that it doesn't really smell that bad
- step 6: measure your waist again
Commercial airliners with pressurized cabins regularly drop the ambient pressure during flight to an equivalent of 7000-9000 feet of altitude. If gas is placed within a closed volume at a pressure equal to the external pressure, and then the external pressure is decreased, a pressure differential will form between the internal and external volumes. The trapped gas will attempt to reduce the pressure differential by either expanding the original contained volume to a new (larger) volume or by reducing the internal pressure by venting gas to the exterior, or a combination of both. As these events happen, the size and location of the pressure differential changes. Over time, this forms a pressure wave, which can be used to perform work.
Stirling engines use these same fundamental principles to operate. They take advantage of the temperature difference between the two sides of the engine to cause the formation of a pressure wave (i.e. they use temperature to change the gas pressure instead of changing the external pressure by flying beans in an airliner). The two pistons then control the movement of the pressure wave between the two sides of the displacement piston to move the piston back and forth, and extract work.
I wonder if Dean's engine can run on beans...
-dave
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From simple observations such as these, come the lessons of life...