....the goal is to get people thinking about the basics first before reaching for the welder first.
hmmmmmm, if only I had found this before reaching for the welder
Methinks we are glossing over the inefficiency of the compressor power requirements for a small gas turbojet engine, particularly in a stationary environment, and ignoring, as well, the energy inefficiency of a shaft transmission to work with just about anything except pure vehicular reaction thrust, since the compressor MUST run at a very high RPM to generate the compression needed to run the turbine. This high RPM also places extreme requirements on bearings -- generally pressure oiled in most supercharger types, and requiring an oil pump, That pump is often driven by wall current in the small supercharger gas turbine conversions I've seen -- no accounting for that energy absorption as well, in terms of fuel efficiency. If you drive the oil pump from the turbine shaft, again there will be transmission losses as well as the pump power requirements.
Now it seems by comparison, we've hobbled the pulsejet here by excluding acoustic effects and concentrating solely on nozzle resistance. A bit like considering only DC resistance in circuits when talking about impedance. The simple mechanical route to inlet losses in pulsejet thrust engines has been to bend the exhaust pipe, or re-orient the inlet aft. Yet I'm quite sure these are not the only possibilities when we start to look at pulsejets as stationary combustors for turbine use, and consider more deeply what we might call inlet reactance.
While I'd be the last person in the world to claim pulsejets are "efficient" users of fuel, I think small gas turbines on a similar scale aren't the best examples of fuel efficiency either, particularly if called on to supply shaft power in useful rpm ranges. The constructional costs and complexity are not comparable, either. FADECs, inconel turbine and compressor castings, high rpm transmissions, tigged stainless, flameholders, etc. are not the sort of thing a backyard builder can typically whip up from scratch, while a working pulsejet turbine actually is. I say bring on the welders!
You know Viv, I'm just funning you, what you've written here is a very good explanation of why an automotive supercharger/pulsejet hybrid isn't a very good combination. Automotive supercharger turbines were never designed to run from pulsejets, and you've helped explain some of the basic reasons why not. But that doesn't necessarily apply to a turbine designed for pulsejet output and reduced RPM.
I of course agree with you after the tongue in cheek above, spreadsheet calculators are exploratory tools just like welders , I wouldn't be without either. Thanks for a good read, and I look forward to further explanations as you go deeper into the subject.