Pulse Combustion Test

More from Luis Mendonca: Pulse Combustion

We just received the following project update by Luis Mendonca including more drawings. For more information contact him through his email.

Mon Sep 10 17:42:25 2001

Hi. Here are some of my ideas of pulse combustion chambers (the complicated ones, now they are much more simple). I will be glad to know that some one will use this ideas. If any questions...just ask.

Luis Mendonça
lmgm@netc.pt

Mon Sep 10 18:18:23 2001

More to come... I will scan my pictures of more 2 Tesla turbines running on water vapor at 10 bar and 150 degrees c, on the power stand at the Coimbra Engineer University

First of all I want to share a couple of photos of our efforts here in Michigan. The first photo shows our Sachs case with all the shaft components assembled and torqued down. The hot rotor flange is on the right, the output pulley on the left. Just below the bearing case are the disks, star washers and hot rotor case end plates -- as we received them from our laser cutter.

The time and effort saved by having a local shop laser cut these parts was well worth the relatively low cost. For our first stage prototyping we are working with a low-cost 836 steel; for final prototypes we'll specify either 316 or 416 stainless for all of these parts.

The next photo shows most of the parts assembled and ready for the hot rotor case ring and end plate.

Test Results

After final assembly of the hot rotor section we modified the outlet of our pulse combustor and attached it to the turbine nozzle. Although the combustor cycled properly, the rotor did not self start. The nozzle being a 1" x 1" square tube did not generate enough directed energetic gas between the plates. Most of the gas energy went around the disks and exited the hot rotor case without transferring power to the disk pack. After grinding a nozzle insert and fitting it into the nozzle tube, the resultant slot impeded the pulse combustion cycle (using low pressure air).

Conclusions

Tesla turbines do not operate under conventional turbine principles. Bladed turbines require large volumes of relatively low velocity fluid, whereas Tesla turbines require lower volumes of accurately-directed high velocity fluid.

Tesla turbines work extremely well with steam, air, or hot gas fed to a slotted nozzle at around 80-160 psi. They do not work well with typical simple pulse combustor techniques.

In order to get pulse combustion to work properly with a Tesla turbine, air and fuel must be delivered to the chamber at pressures suitable to deliver approximately 80-160 psi of hot gas to the working rotor nozzle.

Future Developments

In the coming months we plan to experiment with steam and improved combustion systems for powering up the hot rotor section.

Other Club Member Development Updates

Don Thrasher sent us this photo of his star washer improvements. (For more information on his generator project, see our September 10 article.)

Also, Luis Mendonca sent a number of photos showing some of his work with Tesla turbines. The photos show some of his early work with steam or compressed air driving a turbine; other photos show his more recent work with pulse combustion techniques.