I've got some questions about ionizing air and ion thrusters? Answered
I'm hoping to build an electrohydrodynamic (EHD) thruster ( see here http://blazelabs.com/l-intro.asp#peek )in the near future. Not a lifter like most, but just a thruster designed to create thrust as efficiently as possible. One of the big problems with these devices is obviously energy wasted ionizing air. The thrust of an EHD thruster is T = ID/K where I = current D = distance between anode and cathode and K = the potential needed to ionize the fluid (in this case air). Therefore, increasing the distance will increase efficiency but will decrease absolute thrust. What needs to be done is to separate ionization and acceleration.
The ionization needs to be independent of the ground and I'm not sure how to do this. I need to be able to create a constant cloud of positive ions. It seems though that not having the cathode nearby will require a much higher voltage therefore decreasing efficiency. One Idea I've had so far is to have the positive ionizer, then have a negative grid a few centimeters away and a positive grid a couple millimeters after that one. Hopefully inertia would cause most of the ions to flow through both grids without discharging, and be further propelled. Then several centimeters after that would an electromagnet that accelerates the ions. Any input on whether this will work or better ways to do this?
Finally, I don't fully understand how an ion discharges. If it is energized, the energy has to go somewhere right? So say you have your positive ionizer and a negative sheet right in front of it, when the ions hit the sheet what happens to the energy? Does it get recycled or turned into heat? I'm hoping to figure out some way to recycle the energy from the ions (minus inefficiencies), but I don't have a good enough grasp on this yet. So any ideas about this are greatly appreciated.
I would be very happy if I got this up to 10g of thrust per watt, so input/ideas are appreciated, cheers!