Welcome! Log In Create A New Profile Recent Messages

Advanced

Steam turbine driven turbojet

Posted by novice 
Steam turbine driven turbojet
December 01, 2018 05:32PM
There are several interesting steam turbines powered aircraft projects from 1930-1970s.

[digital.library.unt.edu]

Calculated condenser performance for a steam turbine power plant for aircraft ( 5000 hp steam turbines, 500 mph at 30,000 ft, total cycle efficiency 10-15%).


[digital.library.unt.edu]

Supercritical-water Cycle for Aircraft Propulsion (design of steam turbine driven turbojet aircrafts flying at 30,000-50,000 ft at speed 0.9 Mach -600 mph with total efficiency 20-25%).


[hdl.handle.net]

Steam cycle analysis for nuclear powered turbofan engine ( steam turbine driven turbofan engine designed for flight speed 0.8 Mach and altitude 35,000 ft, with cycle efficiency 20-30%).

In turbopropeller design steam is completely condensing only at speed higher than 250 mph, while turbojet/turbofan engines can work without steam loss even at takeoff. Also, at very high speed, propulsive power of the steam turbojet is significantly higher than its turbine power due to utilisation of waste heat.

I wonder if it is possible to build a small steam turbojet using Besler steam generator, small 200-300 hp steam turbine and high pressure steam condenser placed before the exhaust nozzle.


Re: Steam turbine driven turbojet
December 07, 2018 12:19PM
Hi,
You present some interesting stuff. I'm going to give this some serious thought. One idea I've had for an aircraft engine is to combine the Rankine Cycle with the Brayton Cycle. Gas Turbine Engine Cycle

The condenser of the Rankine is the Q input to the Brayton. This would require a turbine stage added before the exhaust nozzle. Pretty sure you can maintain almost 700 degree F input to the Brayton. I would call this a combined cycle turbine. Further, I would equate this to a Turbofan Engine where the Rankine part is the, albeit Gas Producer, condenser giving up heat. Another way I would call the gas producer is a Turbojet.

Note that achieving super heat with Nuclear PWR is not feasible, my opinion, for a lightweight aircraft engine. The thrust-to-weight ration would not be good, given you have two closed loop systems for safe operation. The T-S diagram shows that and not sure it is feasible.

Another application for this concept would be a bicycle...just a thought! This would be the Turboprop equivalent smiling smiley

Kind regards,
Rick
Re: Steam turbine driven turbojet
January 02, 2019 10:28PM
Here is a calculation of the steam jet engine aircraft from the 1952 study "Basic performance characteristics of the steam turbine-compressor-jet aircraft cycle" by A. Fraas and G.Cohen. Results are showing that this concept is feasible.


Re: Steam turbine driven turbojet
January 02, 2019 10:34PM
Here is the summary of the calculation method.
The design steam pressure is 5000-1000 psi which is quite high. More practical is probably 1500-2000 psi and 1000-1200 F steam.
Engine design speed is 600 mph/Mach 0.9 at 45,000 ft.
Static sea level thrust of such engine per hp of steam turbine is rather low because the steam generator is rated for the cruise power due to weight limitations.



Edited 2 time(s). Last edit at 01/02/2019 11:15PM by novice.


Re: Steam turbine driven turbojet
January 04, 2019 09:01PM
Here is the combined cycle concept...

This takes advantage of the supercritical concept, greater efficiency. Also, this uses HTE to provide greater steam generator efficiency. I would use the Gibbs Free Energy equation to show this.

Note that I can plug the same values and efficiency assumptions into this concept...feasible also. However, this concept is superior in efficiency along with greener.


Re: Steam turbine driven turbojet
January 04, 2019 11:24PM
Steam turbine powered turbojet or turboprop aircraft will not be able to compete with modern turbofan/turboprop aircrafts due to much higher weight and lower efficiency, but it can be used in air racing or to achieve speed record.
Great deal of research on steam aircraft powerplants was done in 1950s. It is suprising that no one tried to build functional steam aircraft using modern materials and technology.

Using WWII motorjet aircraft design it is possible to build steam turbine powered racing aircraft with the top speed over 500 mph. 1200F/3500 psi steam turbine is 2000 hp at 30000 rpm. Air compressor consumes between 25 to 50 percent of turbine power and has pressure ratio between 1.2 to 1.5. Steam condenser is slanted at 30 degrees and works at temperatures 350-450 F and pressures 150-450 psi.
At 20% net turbine efficiency and air temperature rise 180F the required cooling air mass flow is approximately 130 lbs/sec.



Edited 3 time(s). Last edit at 01/06/2019 01:22PM by novice.


Re: Steam turbine driven turbojet
January 22, 2019 11:29AM
Here is objective evidence of Steam Airplane.

Besler Steam Airplane
Sorry, only registered users may post in this forum.

Click here to login

All files from this thread

File Name File Size   Posted by Date  
steam turbojet.jpg 99.2 KB open | download novice 12/01/2018 Read message
steam turbofan.jpg 52 KB open | download novice 12/01/2018 Read message
steam turbojet.png 248.1 KB open | download novice 12/01/2018 Read message
0010.jpg 64 KB open | download novice 12/01/2018 Read message
0020.jpg 96.8 KB open | download novice 12/01/2018 Read message
0030.jpg 110.5 KB open | download novice 12/01/2018 Read message
steam turbine aircraft.jpg 135.7 KB open | download novice 12/01/2018 Read message
compressor jet calculation 1.jpg 69.7 KB open | download novice 01/02/2019 Read message
compressor jet calculation 2.jpg 71.1 KB open | download novice 01/02/2019 Read message
compressor jet calculation 3.jpg 79.4 KB open | download novice 01/02/2019 Read message
compressor jet calculation 4.jpg 73.1 KB open | download novice 01/02/2019 Read message
compressor jet calculation 5.jpg 77.2 KB open | download novice 01/02/2019 Read message
compressor jet calculation 6.jpg 96.7 KB open | download novice 01/02/2019 Read message
compressor jet calculation 7.jpg 97.3 KB open | download novice 01/02/2019 Read message
compressor jet calculation 0.jpg 821 KB open | download novice 01/02/2019 Read message
compressor jet calculation 8.jpg 44.1 KB open | download novice 01/02/2019 Read message
compressor jet diagram.jpg 70.5 KB open | download novice 01/02/2019 Read message
Turbo Fan Concept reduced.jpg 870.5 KB open | download Rick.H 01/04/2019 Read message
180 hp steam aircraft engine 1.jpg 193 KB open | download novice 01/04/2019 Read message
180 hp steam aircraft engine 2.jpg 196.7 KB open | download novice 01/04/2019 Read message
3000 hp Steam Aircraft Turbine.jpg 152.6 KB open | download novice 01/04/2019 Read message
Steam turbofan patent .png 274.6 KB open | download novice 01/04/2019 Read message
compressor_jet.jpg 882 KB open | download novice 01/06/2019 Read message
Steam turboprop racing aircraft.jpg 324.6 KB open | download novice 01/06/2019 Read message