In order to provide a proper "Subject Header" etc, etc.... this is a repost of a repost of a repost. Hope this one works now, since it was in plain-text from the git-go.
First a definition: "Specific impulse" - A term often used in rocketry or munitions, commonly abbreviated (Isp) which rates the efficiency of a propulsion system by the "impulse" (i.e. the change in momentum) per unit of propellant. The numerical dimension of specific impulse is either impulse per unit mass, or impulse per unit time; differing by a factor of g, the gravitational acceleration at the surface of the Earth. For example, the Specific impulse of HOOH monopropellant is about 160-175 (sec), but when burned as a bipropellant with gasoline or kerosene, this figure goes up to about 225, which is slightly less than hydrogen burned with oxygen - yet - the net heat energy of the gasoline is 13 times greater per volume than the heat energy of the peroxide. Huge anomaly. The anomaly, if you need it to be spelled out, is that the heat energy of the propellant is only moderately related to its specific impulse. "Common sense" scientific teaching indicates otherwise. There are only a couple of chemicals where this particular anomaly (of heat energy not correlating to thrust) occurs. A particular terrorist explosive, the name of which need not be mentioned for present purposes, is quietly in the science news lately for a number of security-related reasons. But for alternative energy R&D, the big news of interest is related to a surprising but little-known physical anomaly of the chemical, which is even absent in many older college level textbooks. The explosive is peroxide based, but very different from conventional explosives in that it does not release heat during the explosion. Did the full implications of that feature hit you yet? If not, let me repeat: this chemical explosive does not release heat during the explosion! At least not very much. Irony-of ironies ! Would not it be some kind of poetic justice in the present socio-political climate (i.e. MidWest vs. MidEast, so to speak) if the fear-product of Islamic terrorism led directly to a major alternative-energy advance - which significantly lowered the demand for Middle-Eastern oil? Not as farfetched as one might imagine. Read-on. The phase-change conversion of solid or liquid to gas (as in the steam engine) normally is a product of large energy input and temperature rise, based on combustion; and normally this results in around a 1500-1 to 2000-1 volume change; or correspondingly - a pressure differential of up to 3000 psi max. This volume and pressure swing can be easily converted into energy using an ICE or turbine engine, as is done in power plants all over the world. The process of energy conversion, like combustion, normally obeys Boyle's Law (kind-of): Here is NASA's graphic version of this law: http://www.lerc.nasa.gov/WWW/K-12/airplane/boyle.html But what if the "Law" is broken, and rather explosively? In the spirit of 'swords to plowshares' - the implication of the aforementioned phase-change, of the bomb-anomaly variety is, of course, that when an engine is based on a similar chemical reaction, yet perhaps not quite so dangerous as the one in question, which explosion is employed to convert gas-pressure to torque - then the Carnot limitations and other normal measures of energy/heat content will not apply in the same way as with real heat engines. In other words, our normal assumptions about the relationship of heat energy to kinetic energy are flawed in this limited instance of peroxide-based chemicals. In fact, some observers might be led to opine that there is a window of opportunity for so-called "free-energy" here. However, it is less "free-energy" and more a situation of "time-shifting" - which is concentrating ambient heat (over time in a manufacturing process) into a subsequent large explosion in a comparative instant - rather than anything mysterious or 'aetheric'. But "free-energy" has a nice "ring to it", don't you think? And aether is most likely involved somehow. There is no real violation of sacrosanct thermodynamic laws, at least that is doubtful, as the energy input is often merely shifted in time to the manufacturing stage for the alternative-fuel. For instance, and in a related vein, several companies are trying to exploit compressed air as an alternative energy solution. This is feasible, but not optimum, A compressed air tank serves as a "battery", of sorts, but there is no phase change involved, and compressing a gas seldom returns over 50% of the energy expended. In the situation of compressed air, there is an apparent "entropic expansion" as the air expands, reversing the Carnot assumptions in the engine, but not overall. The compressed-air engine often ices-up, and can show well over 100% heat efficiency (infinite) - IF (big if) - one neglects the energy used to compress the gas. There is a lesser known variant of this phenomenon which DOES utilize phase change, rather than compression, and does not suffer the huge losses of compression but the thermodynamic energy balance is more complicated. This phenomenon is scientifically known as 'Entropic Explosion'. It is reminiscent of the rapid reaction that produces gas in the safety air-bags of cars during accidents, where one does not want to substitute a lesser burn-injury for a major impact injury. The Entropic Explosion (EE) phenomenon may serve to explain how HOOH can be used as a monopropellant rocket fuel when its apparent energy content is low - much lower than the specific impulse of exhaust would indicate. Compared to burning hydrogen in oxygen, the specific impulse of HOOH monopropellant shows about a five to one net advantage, when graphed against heat energy content of the base fuel system. Specific impulse converts directly into torque. There are implications here for expanding HOOH through a turbine in a closed cycle using a tiny amount of H2 (made onboard) as a "pilot" (to ensure complete conversion) and using peroxide as the oxidant/fuel. More on that later, but the idea is that the advantages of the peroxide are so great that they will even support a small onboard electrolysis unit used to create added synergy with the "high-mobility" H2 being added to the mix. But to bring readers here up to date on what is probably a new concept to many (i.e. never before mentioned on this forum, as far as I can tell) : An "Entropic Explosion" is defined simply as an explosion in which the reactants undergo a large change in volume without releasing a large amount of heat. The EE is real, but not a highly favored event thermochemically - as it involves a so-called "entropy burst," which is about as which some might categorize as very difficult to reconcile with the laws of thermodynamics, as they are now applied. Since the torque - which can is captured from such an entropic explosion event can be efficiently captured and converted into electricity or heat, there is an unusual situation involved in computing the thermodynamic balance, giving the superficial appearance of overunity. OU? - No - but the total system may end-up being extraordinarily efficient, compared with combustion. That is the exciting thing in this time-frame of exorbitant fuel costs. You might say that I am "blown away" by the potential advantages of the near-entropic-explosion of peroxides. There could be a better way on the immediate horizon - yet very few scientists are even aware of the possibilities. I would even go so far as to say that there is a distinct possibility that every single power station in operation should be making and burning peroxide with whatever carbon-based (methane, coal, oil, etc) fuel they are using, instead of air ! There is that kind of theoretical potential improvement available. That's the end (or beginning) of today's (actually yesterday's) pregnant-thought, and antonym-of-the-day. Sorry to leave you dangling, if you were expecting more - but one more mention of the x-word, without adding "big-bang" or some other modifier, might constitute... err... carnivore-bait... <g> Jones For those who do not "get it" .. err... that last sentence: http://en.wikipedia.org/wiki/Carnivore_%28FBI%29
