The attached diagram gives figures on the hydrogenolysis pumping cycle
. They are not optimum, just an example. Two 150kN engines power a small hypersonic airliner.
With a single-staged uncooled turbine of nickel alloy, and a single-staged hydrogen pump for simplicity , the cycle still achieves 100bar and 958K=685°C at the main chamber injectors, expanding to 1569m/s for good stirring with air and permanent lighting. The turbopump is as small as a car turbocharger. Alas, it probably needs a gear, maybe hydraulic.
The turbopump can also provide electricity and air to the plane. This combines nicely with the engine starter. I describe quick electric machines therehttp://www.scienceforums.net/topic/73798-quick-electric-machines/?do=findComment&comment=737931
Myrcene C=CC(=C)CCC=C(C)C is a by-product of the paper industry. Nearly as efficient as divinylcyclobutane but with +44°C flash point. A eutectic with pinene would be nice, or with sesquiterpenes for the flash point - mind the pour point for aircraft flying at -70°C.
This cycle burns less hydrogen and more of the dense fuel, which reduces the tanks. I stayed 20% off the soot limit. It can burn more hydrogen to increase the range, then with less pressure and heat at the injectors, or with several stages at the hydrogen pump.
I've split the hydrogen injection at the first pre-chamber, in case hotter hence faster hydrogenolysis is wanted. The optional second pre-chamber provides hotter, denser fuel. If expanding at once from 114 to 100bar, the gas would attain only 493m/s.
Moderate ram compression at the main chamber lets use nickel alloys with little air cooling, as at the prechambers and ducts. The combustor and a part of the divergent are built like a rocket chamber, with a cooling jacket where the hydrogen flows between the pump and the pre-chamber (not detailed on the diagram). Hotter than 2073K is easy. Combustion at uniform pressure is suboptimum.
Scramjet designs adapt to the speed by changing their dimensions and can become ramjets for smaller Mach number by changing their shape - nothing special with the present pumping cycles.
The hydrogenolysis cycle provides insufficient thrust at zero speed, but it is also a means to feed a turbojet with a hydrogen fraction
Ahum again. As it looks, everyone would like molybdenum alloys
for turbines, but up to now they are brittle.
Marc Schaefer, aka Enthalpy