Engine Systems based on TurbX Technology Provide Highest Efficiency, Lowest Cost, Lowest Maintenance, and Lowest Environmental Impact.

TurbX^TM Engines Inc.

September 2001

Support for TurbX engine technology breakthrough is gaining momentum. External agencies that have reviewed this revolutionary technology had the following comments:

From: "Jim Conklin" <conklinjc@ornl.gov>

To: <mw@turbx.com>; <cw@turbx.com>

Cc: <rao-arimilli@utk.edu>

Sent: Wednesday, August 22, 2001 11:25 AM

Subject: TurbX testing to date at the NTRC

A TurbX engine prototype is currently undergoing performance testing at the National Transportation Research Center (NTRC), in Knoxville, Tennessee. The NTRC is a joint operation of the Oak Ridge National Laboratory and the University of Tennessee.

 The thermodynamic cycle on which the TurbX engine operates is called the Atkinson cycle. Using fundamental thermodynamics, the ideal Atkinson thermodynamic cycle shows higher thermal efficiency than either the ideal Brayton (gas turbine) cycle or the ideal Otto (automobile gasoline engine) cycle for all operating conditions. The TurbX engine prototype is being  tested under controlled and realistic conditions to quantify the observed, measured performance characteristics.

The testing program is being performed in a staged manner, first starting with cold flow tests using compressed air, then proceeding to hot flow, or fired tests with natural gas fuel. The cold flow tests are presently being performed at approximately one-quarter the rated speed in order to verify the experimental configuration. Based on these cold flow tests to date (22 Aug  2001), the TurbX engine shows measurable shaft torque and power. The engine ran smoothly, indicating that the air bearing is functional. The measured air  leakage from the air bearing was less than 10% of the main airflow through the engine.

 In summary, cold-flow tests to date indicate that the TurbX prototype engine concept is viable and its components meet the design objectives. The most meaningful TurbX performance results will be observed from the hot-flow  tests, which should be started in a week and completed before 30 Sep 2001.

James C. Conklin, Ph.D.,
Oak Ridge National Laboratory, NTRC
865-946-1340

Rao V. Arimilli, Ph.D.
University of Tennessee, Dept of Mechanical Engineering
865-974-5300

ORNL/TM-2000/116  March 2000

COMPARISON OF PRIME MOVERS

SUITABLE FOR USMC EXPEDITIONARY

POWER SOURCES

T. J. Theiss, J. C. ConklinM J. F. Thomas, T. R. Armstrong

Oak Ridge National Laboratory (ORNL)

A recent invention (Wilson, 1999), a rotating turbomachinery device that operates on the Atkinson cycle, was recently brought to ORNL for evaluation. This particular device cleverly employs the compression, constant volume combustion, expansion and constant pressure expansion processes on one rotating wheel. This particular concept should not have the unsteady loss problem of the pulse detonation engine because supersonic waves are not needed for combustion. Because of the rotary configuration, this concept will not have the disadvantageous power density of the reciprocating piston variation of the Atkinson cycle. Indeed, preliminary analysis of the ideal cycle thermodynamics by ORNL personnel shows that this version of the Atkinson cycle has a power density per unit mass of working fluid greater than that of the ideal Brayton cycle for a given compression ratio. A 15 kW demonstration model of the design has been fabricated and successfully tested under very limited conditions. Thus, the Wilson (TurbX*) configuration of the Atkinson cycle has a very high potential for a heat engine to provide mobile power because of its high efficiency and high power density. For a practical engine, however, there are a number of design and operating characteristics that need to be considered and tested. The non-ideal, real world considerations of friction and unavoidable heat losses will result in a lessening of the ideal efficiency of this like any other thermodynamic cycle, and these non-ideal considerations must be quantified and considered in a practical machine. This Wilson (TurbX*) engine has the potential for improving the fuel efficiency of rotating turbo-machine thermal power conversion devices while decreasing the physical size for a given load. Further analytical and experimental investigation of this concept is highly recommended. This engine design merits further independent testing to quantify the performance characteristics.

The Diesel, Brayton and the Otto cycle engines are known to be very compact and reliable prime movers. It is somewhat surprising that the Atkinson cycle does quite well and scored the highest of all engines considered at all four size ranges.

The Atkinson cycle (as implemented by TurbX*)  is our recommendation as the most suitable engine to pursue even though it is the least mature of the three. Several prime movers should be considered for future developments and may be satisfactory; specifically, the Atkinson cycle, the open Brayton cycle (gas turbine), the 2-stroke diesel. The rotary diesel and the solid oxide fuel cell should be backup candidates. Of all these prime movers, the Atkinson cycle may well be the most suitable for this application but is an immature technology. 

 * Inserted to establish context

NASA Letter November 22, 1996, Christopher A. Snyder, Thermodynamic Analysis Group Team Leader, Propulsion System Analysis Office, Phone 216-977-7018. In this letter Christopher A. Snyder states.

"Your narrative shows a good deal of knowledge about potential issues about turbo machinery (such as high temperature operation of rotating parts as well as cooling and sealing issues)."

"The TurbX Engine compares very favorably with these other engine cycles (and is more efficient that the gas turbine cycles)." 

"The TurbX engine could have the maintenance of a gas turbine with the fuel efficiency (above) that would be a real boost for general aviation as well as other markets."

Richard L. Puster, the Senior Combustion Scientist at NASA Langley states in his letter of January 5, 2000.

“The concept as proposed by Dr. Wilson has potential.” 

“The basic idea is good and has merit.”

“This would be a good engine for light aircraft and stationary power supplies as well as all of the applications of the gas turbine.”

“This is a major development”
”A small efficient gas turbine would have a major effect on efficient transport and fuel utilization.”

Dr. H. Lee Martin, the Executive Director of Tennessee Technology Development Corp. states in a letter of January 5, 2000

“He is extremely excited about the potential of this new TurbX engine.“

“We believe that TurbX technology can have a huge commercial impact.” 

Christopher A. Snyder, Thermodynamic Analysis Group Team Leader of National Aeronautics and

Space Administration, John H. Glenn Research Center, Lewis Field. Further states in an additional Letter of January 10, 2000.

“The concept uses the pressure rise of constant-volume combustion for additional work and efficiency “

 “aerodynamic analysis of the compressor and turbine components is correct “

“The cycle should perform at higher levels “

“Dr. Wilson has suggested other losses, including these losses still suggests a significant benefit for his cycle “

In a proposal to further fund development of the TurbX Enhanced Efficiency Cycle, Titled Development Testing of Patented TurbXÔ Engine Submitted by: R. L. Graves, Manager Advanced Propulsion Technology Engineering Technology Division. DOE/Oak Ridge National Laboratory (ORNL)

 John F. Thomas, A member of the Engineering Testing and Review Team had the following Comments

“Some clear and feasible claims were made that the device can be a very high efficiency.”

“A design for a TurbX engine able to handle high gas temperatures appeared to be quite feasible, as parts continuously exposed to the highest temperature gas are stationary and could be cooled.”

“it is my opinion is that this device could have potential as an efficient engine or a compact and lightweight power source, or both”

J. C. Conklin, Thermodynamic Analysis Expert for the Department of Energy Oak Ridge National Laboratory States.

“TurbX engine concept cleverly substitutes a constant volume heat addition process for the constant pressure heat addition process normally found in gas turbine rotating turbo machinery “

“The thermal efficiency and power density can be proven as always higher for any given compression ratio under ideal conditions than the gas turbine that typically operates on the Brayton cycle”

“Interestingly, the thermal efficiency and power density at a constant shaft

speed are a function of the load for this ideal cycle, which is not the case for the gas turbine. This inherent characteristic allows for fast load changes at constant speed by simply modulating the fuel flow rate, which is an easily controlled parameter”

“TurbX engine concept will have a higher allowable turbine inlet temperature, and thus high thermal efficiency, because the turbine components are not exposed to a constant high temperature”

“TurbX concept engine clearly has the distinct advantages of high thermal efficiency and high power density”

“This TurbX engine has the potential for improving the fuel efficiency of rotating turbo-machine thermal power conversion devices while decreasing the physical size for a given load”

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