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Name: Bill
Status: other
Age: 20s
Location: N/A
Country: N/A
Date: 2000-2001


Question:
I would like to learn about cavitation. It is my understanding that in a cavitation event, as the bubble colapses the pressure in the bubble approaches infinity as the bubble's size approaches zero. And that as the pressure increases so does the temperature. So at the molecular level as the bubble size approaches the size of one water molecule the temperature at that point could be hotter than the sun. My first question would be, is my first assumpion correct? My second question is, if indeed a cavitation event causes tremendous temperatures, is that enough to break molecular bonds, or even atomic bonds? If the answer to my second question is affermative then it is possible to generate more energy out of a cavatation event than went into making it?


Replies:
Yes, cavitation can generate tremendous temperatures inside the collapsing bubble, even greater than at the surface of the sun. This is easily enough to break covalent (molecular) bonds. Hovever, it does not approach the temperatures necessary to induce nuclear reactions. The only reason that a self-sustaining thermonuclear reaction can occur on the sun is that there is so much fuel present. At the temperature of the sun, very, very little of the material reacts at any given time. That is why the sun can sustain its energy output for so many billions of years.

In other words, ultrasonic cavitation will not generate more energy than it consumes by inducing nuclear reactions.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois


An interesting experiment, but it is unlikely that are getting more energy out than you put in. And, as you've indicated, 20% is a lower limit on your estimate. Two areas to double check are:

1. The accuracy of the instruments you are using to measure the power you are putting into the system

2. The calculations you use -- are your units consistent? For example you mention watt-hour meters for energy measurement and you look at the temperature rise of the drum of water. Do you have the correct heat capacity for water. What units is the heat capacity in? I doubt that it is in Watt-hours / (deg C - kg). More likely it is in Joules / (deg C - kg) or calories / (deg C - g). the heat capacity of water is 1 calorie / (deg C - g). Assuming a 55 gal drum you could have as much as 220,000 g of water. A temperature rise of 1 deg C (are you using Fahrenheit thermometers? -- another conversion!) requires 220,000 calories or ~920,000 Joules, or ~260 Watt-hours. These numbers are very approximate and are given only as an independent check on your figures.

Alternatively, the heat capacity of water is ~0.0012 Watt-hours / (deg C - g) or 0.00065 Watt-hours / (deg F - g) or 0.30 Watt-hours / (deg F - lb)

Greg Bradburn


I am still a little confused about the "Apparatus" in your experiment. Has the test been run without any cavitation taking place and the results recorded. We all know that your "perpetual motion machine" that you have created cannot be correct. There is also the possibility that these meters you are using are taking the uncalculated energy, you mentioned that you "apparatus" also has a watt-hour meter for the motor, why is a second motor needed and what exactly does this "Apparatus" do?? The other thing is you are ignoring the loss of energy to the environment which may make up this 20% that is constantly lost, pumps are not the most efficient machines in the world! If you were to use a "black box" around the whole room that this test is in and measured the total energy input- energy contained within the box you would find it is equal. there is no way to create excess energy from nothing.

Michael Baldwin



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