Research Papers

Preparing for the Future: Reducing Gas Turbine Environmental Impact—IGTI Scholar Lecture

[+] Author and Article Information
Nicholas A. Cumpsty

 Imperial College, London, UK SW7 2AZ

The U.S. Government Energy Information Administration released data in 2008. Assuming 2006 consumption, it can be calculated that accessible coal can meet consumption for about 200 years, while natural gas can meet consumption for about 60 years. If, however, natural gas replaced coal the proven reserves of natural gas would be exhausted in about 30 years.

A380-800, A340-500, A340-600, B777-200ER, B787-base, B787-stretch, B777–300, and B747-400.

From the Boeing website, it may be seen that the B787-8, B787-9, and B787-3 are designed for ranges of 7500–8200 nm, 8000–8500 nm, and 2500–3050 nm, respectively. From the Airbus website, the ranges for the A350-800, A350-900, and A350-1000 are 8300 nm, 8100 nm, and 8000 nm, respectively

Note added to Journal paper in proof. Bohr's observation, quoted at the opening of the paper, is born out here. It now looks as if unconventional sources of natural gas (shale gas, tight gas, coal-bed methane) are abundant and more accessible than had been widely realized. Reports suggest that these unconventional sources of natural gas may be more abundant than the conventional sources used hitherto, and as a result the use of coal for electricity generation may be much reduced.

J. Turbomach 132(4), 041017 (May 11, 2010) (17 pages) doi:10.1115/1.4001221 History: Received July 26, 2009; Revised July 27, 2009; Published May 11, 2010; Online May 11, 2010

In the long term, the price of fuel will rise and it is now urgent to reduce carbon dioxide emissions to avoid catastrophic climate change. This lecture looks at power plant for electricity generation and aircraft propulsion, considering likely limits and possibilities for improvement. There are lessons from land-based gas turbines, which can be applied to aircraft, notably the small increases in efficiency from further increase in pressure ratio and turbine inlet temperature. Land-based gas turbines also point to the benefit of combining the properties of water with those of air to raise efficiency. Whereas the incentive to raise efficiency and reduce CO2 will force an increase in complexity of land-based power plant, the opportunities for this with aircraft are more limited. One of the opportunities with aircraft propulsion is to consider the whole aircraft operation and specification. Currently the specifications for new aircraft of take-off and climb thrust are not fully consistent with designing the engine for minimum fuel consumption and this will be addressed in some depth in the lecture. Preparing for the future entails alerting engineers to important possibilities and limitations associated with gas turbines which will mitigate climate change due to carbon dioxide emissions.

Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

Temperature-entropy chart for steam power plant (1)

Grahic Jump Location
Figure 2

Thermal efficiencies of simple gas turbines from Wilcock (2). Overall pressure ratios of 60 for broken line, 45 for solid line, and 30 for dotted line. (a) black is ηs=100%, no cooling; (b) blue ηs=90%, no cooling; (c) red ηs=90%, “advanced” cooling.

Grahic Jump Location
Figure 3

Alstom GT24/26 combined-cycle gas turbine, with reheat of gas in a second combustor after HP turbine (1)

Grahic Jump Location
Figure 4

Temperature-entropy diagram of Alstom GT24/26 with reheat of gas after HP turbine (1)

Grahic Jump Location
Figure 5

Rolls-Royce WR21 engine for marine propulsion. VAN refers to variable area nozzle, a means to vary power output and speed (4)

Grahic Jump Location
Figure 6

The Rolls-Royce WR21 marine gas turbine (4)

Grahic Jump Location
Figure 7

A simplified scheme using a gas turbine for power generation with CO2 separation with oxy-fuel combustion (9)

Grahic Jump Location
Figure 8

A simplified scheme for power generation based on gasification of coal and separation of CO2 from the fuel (8)

Grahic Jump Location
Figure 9

The link of sfc and overall efficiency with thermal efficiency and propulsive efficiency (10)

Grahic Jump Location
Figure 10

Specific fuel consumption versus bypass ratio at cruise for different fan pressure ratios. Core conditions held constant, opr=40, TET=1475 K.

Grahic Jump Location
Figure 11

Core conditions for maximum take-off at ISA+15 K for data core with different fan pressure ratios at cruise. The solid line is take-off thrust of 0.3MTOW, and the broken line is 0.275MTOW.

Grahic Jump Location
Figure 12

Fan pressure ratio at MTO and TOC (data core)

Grahic Jump Location
Figure 13

Corrected mass flow for max. take-off and top of climb divided by corrected mass flow at cruise (data core), FnTO=0.3MTOW

Grahic Jump Location
Figure 14

Fan operating characteristic with design fpr=1.8 at cruise, data core. MTO is for FnTO=0.3MTOW, and MCL is TOC at 500 ft/min.

Grahic Jump Location
Figure 15

Fan operating characteristic with fpr=1.5 at cruise, data core. MTO is for FnTO=0.3MTOW, and MCL is TOC at 500 ft/min.

Grahic Jump Location
Figure 16

The proposed CLEAN engine, part of EU EEFAE program (15)



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In