I have been following the work of Rossi and DGT for some time. Rossi always speaks of thermal runaway as an issue and I am inclined to believe him in this case.
Consider the following scenario: 1) The present temperature of the core defines the level of LENR activity and thus the heat output. 2) Assume that the core temperature rises a differential amount due to noise or some other perturbation. 3) The heat output rises slightly due to the increase in differential temperature of the core. 4) This new differential heat flux due to the differential temperature rise flows through the thermal resistance it encounters to the ambient. 5) The heat flow through the thermal resistance generates more temperature differential than the initial beginning differential. 6) This process continues as the temperature of the core rises and the heat output increases until something occurs that breaks the gain. In this case it is true that the heat is extracted from the device by radiation which is proportional to the forth power of absolute temperature. It might be possible to carefully adjust the thermal resistance path from the core to break the loop gain back to 1 at a good demonstration temperature as a consequence of the high order (4th) sink. Lets take a look at the other direction that the temperature and heat output might take: 1) A small differential core temperature drop occurs. 2) The output heat generated by the LENR activity falls by a differential amount due to the drop in temperature. 3) Less heat now flows through the thermal resistance as above and therefore the temperature of the core drops. 4) With a positive feedback gain of 1 or more, the temperature drops more than the activating differential disturbance. 5) The process continues as the temperature of the core falls toward room temperature and the LENR activity goes away. 6) The output latches at this stop since there can be nothing available to start an upward movement. The high power radiation effect (forth order with temperature) might result in a soft landing before reaching room temperature, but that is not easily determined without experimentation. Makes you miss the good ole days with water baths! If we happen to see the second scenario while testing, our demonstration does not enhance LENR proof to many skeptics. An active system such as the ones suggested by some of our members would likely prevent such a problem. I suspect that now would be a good time to attempt to understand what it would take to cause the first scenario to reverse from its relatively stable operating point and begin a transition toward room temperature. It will take some modeling and/or serious consideration to determine how strongly the Celani device tends to remain at the high temperature operating point. There must be some level of disturbance that will get us into trouble; the question is how much. This same thought process suggests that the latest photo of Rossi's device might be legitimate. If he has adjusted the cylinder sizes to rely upon radiation as the heat exhaust path, then he may be relying upon that same high order radiation effect as discussed above. Now, exactly how do you use this type of process within a useful closed system? Dave -----Original Message----- From: Jed Rothwell <[email protected]> To: vortex-l <[email protected]> Sent: Wed, Aug 22, 2012 1:51 pm Subject: Re: [Vo]:What a self-sustaining demonstration by Celani might accomplish [email protected] wrote: > You can prevent these problems by starving the device of fuel. I.e. control the > fuel supply rate such that it doesn't get a chance to self destruct . . . I assume the fuel is hydrogen. I do not think it is possible to admit such a tiny amount of hydrogen into the cell that it would affect the reaction rate. It would have to be fairly strong vacuum. I do not think there is evidence that this reaction can run away, or that it needs input to keep going or to prevent runaway. It needs input to trigger the reaction, and to keep the present cell at operating temperature, however both this reaction and the electrochemical one seem to work fine in the absence of input. - Jed
