Variable Geometry in Miniature Gas Turbine for Improved Performance and Reduced Environmental Impact

Szymon Fulara,Marian Gieras,Maciej Chmielewski

doi:10.3390/en13195230

Abstract

A miniature gas turbine (MGT) is proposed as a promising future energy source. Increasingly stringent requirements related to harmful combustible gas emissions and a trend towards improved energy generation efficiency drive the quest for new MGT technologies. Variable geometry systems are promising due to enhanced heat management and flow control. Variable combustor cooling and dilution holes together with the variable area nozzle (VAN) system allow for the improvement of gas turbine performance and reduction in pollutant emissions. The proposed systems are based on hot-section geometry changes, in which the size of the combustion chamber holes and turbine nozzle angle can be adjusted. Component and module experimental research were performed at the Warsaw University of Technology, on an MGT test stand. A significant decrease in fuel consumption (up to 47% reduction) and harmful nitrogen oxide emission reduction (NO–by 78% and NO2–by 82%) were achieved. These results are related to combustor turbine inlet temperature (TIT) increase up to 1230 K. The tests of the variable geometry systems have also shown an impact on gas turbine power and specific fuel consumption.

Highlights

Gas turbines exhibit an extraordinary power-to-weight ratio, and in the foreseeable future, they will be a promising source of clean, reliable and relatively cost-effective energy
The advanced systems that increase gas turbine efficiency include applications known from aviation: bleed valves and active clearance control, advance compressor variable geometry, low emission combustion chambers, improved cooling of turbine nozzles and blades; inter-stage cooling, water injection and heat exchangers known from industrial gas turbines
The results presented in this article show that the discussed hot section variable geometry systems significantly impact the thermal efficiency and emissions of the miniature gas turbine

Summary

Introduction

Gas turbines exhibit an extraordinary power-to-weight ratio, and in the foreseeable future, they will be a promising source of clean, reliable and relatively cost-effective energy. Their applications can be found in power plants, aviation and maritime transport. The advanced systems that increase gas turbine efficiency include applications known from aviation: bleed valves and active clearance control, advance compressor variable geometry, low emission combustion chambers, improved cooling of turbine nozzles and blades; inter-stage cooling, water injection and heat exchangers known from industrial gas turbines. In the case of land-based gas turbines the advanced combined cycle gas turbine (CCGT) systems increases overall efficiency to 42–62% depending on turbine models, power plant altitude, ambient temperature and applied supplementary systems [1,2,3].

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Results

Discussion

Conclusion