A Critical Review of NOx Correlations for Gas Turbine Combustors

The effect of inlet temperature, pressure, air flowrate and fuel-to-air ratio on NOx emissions from gas turbine combustors has received considerable attention in recent years. A number of semi-empirical and empirical correlations relating these variables to NOx emissions have appeared in the literature. They differ both in fundamental assumptions and in their predictions. In the present work, these simple NOx correlations are compared to each other and to experimental data. A review of existing experimental data shows that an adequate data base does not exist to evaluate properly the various NOx correlations. Recommendations are proposed to resolve this problem in the future.

Advanced Labyrinth Seal Design Performance for High Pressure Ratio Gas Turbines

Labyrinth seal air leakage performance in current and advanced high pressure ratio gas turbines is directly related to the limitations of current available sealing technology. Sea design technology has not kept pace with the gas turbine major component advances. Therefore, an investigation was undertaken to design, fabricate and test several unique labyrinth seal concepts intended to decrease leakage through higher efficiency. The approach used in the unique designs for improving the efficiency of labyrinth seals involved increasing the internal cavity turbulence of the seal. The program involved three test and evaluation phases: (a) water tunnel studies; (b) static air rig tests; and (c) dynamic air rig tests. The water tunnel rig provided an economical method of screening the unique candidate designs. The most promising configurations from the water rig were fabricated and tested in the static air rig. Those configurations demonstrating a significant reduction in seal leakage over current designs were tested dynamically up to 786 ft/sec in an air rig to assess the effects of rotation. The results of this program effort show that each of the unique seal designs achieved lower leakage rates than a standard baseline step seal. In addition the dynamic seal test results show minimal effect on leakage due to rotation up to 786 ft/sec.

Hydrodesulfurized Residual Oils as Gas Turbine Fuels

Catalytic hydrogenation was developed to remove sulfur from residual oils, but it also reduces the fuel viscosity and removes most of the vanadium, sodium, nitrogen, and other impurities. Eleven desulfurization operating worldwide are producing over 325,000 bbl/day (51,692 m3/d) of boiler fuel with 1 percent sulfur, starting with residual of 4 percent sulfur content. More severe versions of the process are available to reduce sulfur content to 0.3 or 0.1 percent. Hydrodesulfurized residuals should be attractive fuels for gas turbine of combined-cycle power plants. With fuel sulfur content reduced to meet emissions standards, fuel constituents responsible for turbine corrosion and deposits are also minimized.

Gas Turbine Engine Internal Air Systems: A Review of the Requirements and the Problems

This paper reviews the requirements and the problems of engine air systems design. It considers, very briefly, the overall requirements of an engine air system and also the interface of the system with the overall thermodynamic performance of an engine. It then considers aspects of air systems design which are of particular interest to the design and performance of modern high pressure engines. Problem areas such as the cooling air transfer systems, extraneous cooling air heat absorption and transient thermal analysis of engine rotor and stator assemblies are considered.

The Effect of Inlet Temperature and Pressure on an Industrial Turbine Engine Exhaust Emission

The effect of variation of inlet temperature and pressure on exhaust emissions from an industrial gas turbine was determined experimentally. Testing was done in a controlled environment test cell. In addition to temperature and pressure, the influence of two fuels, JP-5 and DF-2, was evaluated. A data matrix of 81 engine operating points was obtained, from which emissions were correlated with engine inlet conditions using regression analysis techniques. The data are analyzed to show how these inlet variables affect compliance with the EPA exhaust emission standards for aircraft and stationary turbine engines.