guest blogger john hare
Posting here has been a privilege with the quality of people responding. You all deserve a chance to say I told you so on my minor hardware attempt. Make your best guess at what happens for the privilege of saying it later. Anybody that always says nothing before, and then says they could have told me about that problem later, don’t bother this time.
You know I have an interest in pumps in general and turbopumps in chamber in particular. Yesterday I left the drawings and deposit with the machine shop for the rotating portion of a cold flow test rig.
The intent is to use shop air at 125 or so psi to pump water into the test chamber. The water will be in an unpressurized barrel with initially 4 feet of head pressure, or less than 2 psi for initial feed. The water enters through the bearing shaft and exits through the holes in the turbine blades that serve as pump passages. The turbine disk is 2 inches diameter with the blades 3/8 inch long. Air and water exhaust through a single port under the turbine blades. The compressed air enters through a diffuser where the injectors would be in a real engine. The diffuser is to simulate the chaotic flow in an engine without turbine nozzles.
If everything works exactly right, I should get a lot of water introduced to the chamber at 50-75psi. We know that it won’t work right. Your predictions as to where it goes wrong should be good for a little fun. My prediction is that I get all the parts together, and then see a gotcha before hooking up the water.
If the unit spins and produces anything at all, I intend to try various numbers of ports and turbine nozzle arrangements to see what happens. I might be able to build a compressed air/kerosene hot fire unit in a year or three if this kludge works. A real rocket ain’t happening on my budget, skill level, and general cowardice towards dangerous things I have no experience with.