Greetings All! This is rather lengthty, but I am really serious, so if you have the time to read it, I'll be most grateful.
Having watched the list for some time (and ARocket too), I have become very interested in designing and building a prototype kerosene/H2O2 engine, which can burn for minutes (as opposed to seconds for many amateur solids). To be more precise, I am for now leaving out the issue of pump fed vs. pressure fed, and only concentrating on the pressure chamber, cooling, and nozzle, in an attempt to make a design which allows for relatively easy manufacturing and reusability. The engine will have to be regeneratively cooled. I need a little help to get started ... mostly pointers to existing sources of information (text, drawings) I guess. I won't be doing it by myself, rather I would like to take a managing role for such a project, so any information is welcome. So far I have the following observations/conclusions/unanswered questions: - Propellant availability: kerosene/JET-A1 not a problem. 70% H2O2 readily available here in Denmark, 86% H2O2 available from Germany in bulk by railroad waggon (hmm!). Is it at all feasible to try work with 70% H2O2 and get satisfactory results for serious prototype rockets? I've seen amateur rockets being sold over the counter in the US running on 50% H2O2 and gasoline, but they are only good for a couple of 1000 ft. - Propellant mixing ratio, temperature and pressure generated for given mix and volumetric flow. I assume this highly depends on pressure chamber volume vs. nozzle restriction? Isn't the goal to achieve as high pressure as possible, given constraints by ability to cool the walls, and mechanical strength of overall construction? - How do I calculate the theoretical Isp and thrust for say: X amount of H2O2 run through copper catalyst, injected with Y amount of kerosene into a cylinder of 100 ccm, with a 4 cm2 nozzle throat, and a nozzle ratio of 1:10 ? (numbers just shown for example, they may have no resemblance to anything possible...) Is the idea to say: 1 gram of 70% H2O2 will produce X liters of steam and Y liters of oxygen, and in a chamber with a given volume this will result in Z bars of pressure. With a continous feed of this amount, chamber pressure will be steady at somewhere below Z, due to the flow out through the nozzle. But won't this increase in pressure (and hence temperature) assist further in the decomposition of the H2O2, and hence produce more volume? And then there's the added component of the kerosene... I have to assume that this does not scale linearly, so is existing knowledge formed from practical experimentation, or can it really be calculated? How about CFD (Computational Fluid Dynamics) simulations? Any publicly available results, formulas, programs or PC spreadsheets out there I can start from? (If you would like to share this we me on a private basis, I will respect that too.) - The pressure in the cooling system will be higher than in the pressure chamber (otherwise the kerosene can't be injected). But how much higher to achieve satisfactory vaporization? How do I calculate the size of the injectors, ie. drilling size, versus volume and feed pressure? Is flow volume a linear function of pressure (counting out flow restrictions of tubing, etc.)? - The overall engine is thought to be machined in aluminum, however with inner walls of the pressure chamber and nozzle throat in copper, for sake of good heat transfer. Any special considerations here? I better stop here now. I guess this is more than enough for one mail ;-) Again, your comments and thoughts are highly appreciated. This is a wonderful forum!! Thanks - Henrik Denmark ---------------------------------------------------------------------- Henrik Schultz Schultz Software Senior Systems Architect IT Services and Solutions http://www.schultz-software.dk/ Tel: +45 3963 4856 _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
