Small-sized Gas Turbine Engine Research Articles

Selection of Numerical Simulation Methodology for the Small-Size Gas Turbine Engine Cycle

Selection of Numerical Simulation Methodology for the Small-Size Gas Turbine Engine Cycle

Numerical and Experimental Studies of the Plate Heat Exchanger Module of the Small-Sized Gas Turbine Engine with Heat Recovery

Numerical and Experimental Studies of the Plate Heat Exchanger Module of the Small-Sized Gas Turbine Engine with Heat Recovery

Method of manufacturing a plate heat exchangerfor a small-size gas turbine engine with heat recovery

Method of manufacturing a plate heat exchangerfor a small-size gas turbine engine with heat recovery

Application of the vacuum casting technology in the production of small-size gas turbine engine blade machines

The application of casting technologies in the production of parts and assemblies of small-size gas turbine engines is justified in the paper. The technology of vacuum casting in gypsum molds was tested during the production of an experimental centrifugal compressor of a small-size gas turbine engine. On the basis of a 3D model of the designed centrifugal compressor, computational studies of vacuum casting were carried out and rational parameters of the technological process were determined. Prototypes of the developed centrifugal compressor of a small-size gas turbine engine were made. The results of calculations and the performed technological experiment confirmed the fill rate of the gating form and the absence of short pour. The distribution of shrinkage porosity and cavities corresponds to the design values and is concentrated in the central part of the casting that is subjected to subsequent machining. The area of the blades, disc and sleeve is formed without defects. The use of casting technologies in the production of parts and assemblies of small-size gas turbine engines assures the required quality with a comparatively low price of the finished product, making it possible to achieve the balance between the cost of the technology and the quality of the product made according to this technology.

Combustion chamber development features for converted small gas turbine

Conversion and modernization of a gas turbine engine involves solving a number of tasks, one of which is the development of a combustion chamber for operation on various gaseous fuels. The complexity of solving this problem is associated with a variety of interrelated processes occurring in the CC, which are complex and insufficiently studied. The work on the small-size gas turbine engine CC is even more complicated by the lack of a generally accepted and well-developed finishing technique typical of large gas turbine engines, which is emphasized both in domestic and foreign works. The report considers the main approaches to classifying the dimensions of combustion chambers of gas turbine engines [1] according to various criteria, namely: to the power type size (according to CIAM)Classification based on the reduced air flow through the compressor. The criteria included in the classification are analysed, in relation to the implemented designs, the most objective classification is selected for further consideration of the design of the combustion chamber of a small-sized gas turbine engine when converting it to gaseous fuel. The features and technical limitations of converting the combustion chamber from liquid to gaseous fuel are considered, which is an urgent task against the background of gasification programs of the fuel and energy complex in the Russian Federation. Attention is paid to the factors that have the greatest impact on the environmental characteristics of the converted combustion chambers.

ИССЛЕДОВАНИЯ КОМПРЕССОРНОЙ И ТУРБИННОЙ ЧАСТЕЙ ТУРБОКОМПРЕССОРОВ С ОБЩИМ РАБОЧИМ КОЛЕСОМ ДЛЯ ПРИМЕНЕНИЯ В ДВИГАТЕЛЯХ И ЭНЕРГОУСТАНОВКАХ

To develop engines and power plants, the issues of improving engines through the use of a new type of turbomachines – turbo-compressors with general impeller (TCG) have been considered. There is another name for this type of turbomachine – a single-disk turbo-compressor (STC), although for bladed machines it is not the disk that is important, but the entire impeller. For example, a diagram of the simplest small-sized gas turbine engine using TCG is shown. For the systematization of relatively efficient TCG schemes, a classification has been developed and is given in the article, of possible schemes for a turbocharger with a common impeller. To implement one or another flowing pattern in the impeller, it is necessary to select the appropriate shape of the impeller blades and the location of the nozzle, exhaust, suction and discharge channels relative to each other. Depending on the direction of movement of the gas flows, turbo-compressors with a common impeller may have two flow patterns in interscapular impeller space – direct-flow and counter-flow. If the directions of the gas and airflow coincide to the axis of rotation of the impeller, then the flow pattern in the TCG is direct-flow, with opposite flow flows it is countercurrent. For carrying out the enlarged gas-dynamic calculation of TCG, formulas are given that make it possible to calculate the circumferential force arising on the blades of the impeller in the compressor and turbine working channels of the TCG. Also, formulas are given, with correction factors, for calculating the power factor of the compressor part and the load factor of the turbine part. In the process of computational and experimental studies, the characteristic of the compressor part of the TCG experimental model was obtained. If the ratio of the grating width to the average diameter of the working channel is overestimated, it is necessary to supplement the formula for calculating the compressor power factor with a correction factor. The test results of the compressor part of the TCG experimental model showed good agreement between the calculated and experimental values. Studies have shown that a turbocharger with a common impeller can be used as of gas turbine engines and in a turbo-supercharging system of a capacity internal combustion engine with not high supercharging.

Experience in using anisotropic properties of composites in engineering the compressor impeller of a small-size gas turbine engine

The use of composite materials in modern aircraft and rocket engines is one of the most promising areas. Low density and high strength characteristics of composite materials are crucial when choosing a material for small-sized compressors. The main ability to bear the load of the composite material is provided by the reinforcing fibers of the filler. The greater the percentage of filler fibers has a particular orientation, the higher the strength and rigidity of the product in this direction. If the part is loaded with forces applied primarily in one or two directions, it makes sense to create a material with anisotropy of properties that will exactly match the applied loads. For example, the disk and blades of a centrifugal compressor operate under the action of centrifugal force and gas pressure. In this case, to manufacture a centrifugal compressor impeller from composite materials, it is only necessary to redistribute the fibers in the part space in such a way as to create an optimal anisotropy of properties. This article describes the procedure for selecting the optimal orientation of reinforcing fibers in the impeller of a centrifugal compressor of a small gas turbine engine.

Circumferential Distortion (Temperature) Reduction of a Small-Size Gas Turbine Engine Combustion Chamber by Numerical Experimentation

Circumferential Distortion (Temperature) Reduction of a Small-Size Gas Turbine Engine Combustion Chamber by Numerical Experimentation

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЙ КОМПРЕССОРНОЙ И ТУРБИННОЙ ЧАСТЕЙ ТУРБОКОМПРЕССОРОВ С ОБЩИМ РАБОЧИМ КОЛЕСОМ ДЛЯ ПРИМЕНЕНИЯ В МАЛОРАЗМЕРНЫХ ДВИГАТЕЛЯХ

It is considered the issues of improving small-sized engines through the application of a new type of turbomachines – turbo-compressors with general impeller (TCG) to develop engines and power plants. For example, it is shown a diagram of the simplest small-sized gas turbine engine using TCG. For the systematization of relatively efficient TCG schemes, a classification has been developed and is given in the article, of possible schemes for a turbocharger with a common impeller. The classification is based on 5 possible directions of movement of the working medium in the blade apparatus – axial (parallel to the axis of rotation of the machine), centrifugal, centripetal, diagonal and tangential. To implement one or another flowing pattern in the impeller, it is necessary to select the appropriate shape of the impeller blades and the location of the nozzle, exhaust, suction and discharge channels relative to each other. Depending on the direction of movement of the gas flows, turbo-compressors with a common impeller may have two flow patterns in interscapular impeller space – direct-flow and counter-flow. If the directions of the gas and airflow coincide concerning the axis of rotation of the impeller, then the flow pattern in the TCG is direct-flow, with opposite flow flows it is countercurrent. For carrying out the enlarged gas-dynamic calculation of TCG, formulas are given that make it possible to calculate the circumferential force arising on the blades of the impeller in the compressor and turbine working channels of the TCG. Also, formulas are given, with correction factors, for calculating the power factor of the compressor part and the load factor of the turbine part. In the process of computational and experimental studies, the characteristic of the compressor part of the TCG experimental model was obtained. The test results of the compressor part of the TCG experimental model showed good agreement between the calculated and experimental values. Studies have shown that a turbocharger with a common impeller can be used as part of small-size gas turbine engines and in a turbo-supercharging system of a small-capacity internal combustion engine with not high supercharging.

Improving the Efficiency of Aviation Products Design Based on International Standards and Robust Approaches

The article considers the possibility of using QFD, robust design and other modern approaches for designing innovative aviation products. As an example, the projected unmanned aerial vehicle and engine, as its key part, are considered. Based on expert evaluation and analysis of benchmarking data, the main consumer requirements for UAV and a small-size gas turbine engine were identified. It is also necessary to pay attention to such general requirements as low noise, low emission of harmful substances (CO and NOx). The use of international standards of the ISO 16355 series as a methodology and basis for improving design efficiency is discussed. The results and conclusions can be applied to various types of aviation products, as well as used in other industries.

Investigation of the Ni-Co-Cr alloy microstructure for the manufacturing of combustion chamber GTE by selective laser melting

Selective laser melting implementation by gas turbine engine combustor chambers manufacturing difficult machining material Ni-Co-Cr alloy is an actual task to directly form complicated shapes. The paper shows the study of Ni-Co-Cr powder such as chemical, morphology, grain size, flow rate, and pour density analysis. The study results demonstrate the structure of Ni-Co-Cr alloy manufactured by selective laser melting in vertical and horizontal directions in original condition and after hot isostatic pressing. It is established that hot isostatic pressing offers the possibility to reduce the porosity and improve the mechanical properties. The influence of the hot isostatic pressing process on the density and microstructure of Ni-Co-Cr alloy is investigated by means of X-ray phase analysis and scanning electron microscopy. The results of the experiments show that the majority of the pore can be densified by means of hot isostatic pressing. The study presents the SLM technology implementation by producing the small size gas turbine engine combustor chamber.

Simulation of Pollutant Emissions in a Small-Size GTE Based on the Reactor Network Model

The results of simulation of the NOx and CO formation in a small-sized gas turbine engine are presented. A comparison of the results of CFD calculations with experimental data showed that calculations in standard three-dimensional formulation in combination with partitioning into a network of reactors can be used to simulate NOx and CO formation. When using the JetSurf 2.0 chemical reaction mechanism, satisfactory agreement between calculated and experimental data is achieved with a number of elementary reactors above several hundreds.

Micro gas turbine engine imitation model

Benches are widely used in the process of creating automatic control systems (ACS) for gas turbine engines (GTE). The engine work is simulated via mathematical models. The model is supposed to be highly accurate in conditions of quite rapid calculation of the engine main parameters in both steady-state conditions and transient processes. A simulation model of a micro gas turbine Jet Cat P-60 engine is presented in the article. The model is based on the data obtained from generalized engine performance. A simulation model of a small-sized gas turbine engine is developed by plotting the rotor acceleration against the rotor rotational speed and the combustion chamber fuel consumption at each moment of time. The results of simulating the engine operation are compared with the experimental data obtained with increasing the GTE operation mode. The average modeling error value is obtained: 1.04% (ambient temperature is 288 K), 2.58% (249 K). It is acceptable for an adequate simulation of the GTE bench performance.

Uprating the Frontal Thrust of a Spherical Gas-Dynamical Resonator-Pulse Amplifier

Calculations were carried out with application of current numerical methods and with the use of scientific-technical developments of a gas-dynamical resonator-thrust amplifier. The possibility of creating an exit device with a resonator for a small-size gas-turbine engine that in flight provides for thrust uprating by no less than 6% via gas mass attachment in the pulsating process is shown. In this way the size–mass characteristics of the exit device are preserved in the process.

Air starting system of small-size gas turbine engine

To meet the requirements for starting a mid-flight (GTE) of a reusable unmanned aerial vehicle (UAV), we developed an air starting system according to the scheme with the direct feed of compressed air to the turbine rotor blades. The system is an alternative to the commonly used powder or electrical starting systems of a small-size GTE of UAVs. The paper gives the results of experimental studies to determine the reliable starting feasibility and methods for determining the parameters required for starting the GTE of UAVs.

Numerical Simulation Application for the Design and Fine-Tuning of Small-Sized Gas Turbine Engine Combustor

The small-sized GTE are used more and more both as the basis of power plants and power machines for various purposes. The technical and operational characteristics of these engines are largely determined by the design quality of their combustion chambers (CC). One of the most advanced methods of CC scientific investigation is the bench testing. However, such CC operation study is complicated by labour-intensiveness of an experiment and its significant costs. Therefore, in recent years GTE designers started to use widely the numerical simulation for these purposes. However, the level of such calculation development does not allow often to solve the issue of CC fine-tuning in order to achieve the required parameters. It is also difficult to determine the reliability degree of such calculations. The preliminary calculation of the combustion chamber was performed first of all. Its purpose is the CC shape development and its determination of its geometric dimensions. At that, the main requirement was to ensure the possibilities of one CC placement between the previously-designed compressor and the turbine and the performance of a whole set of technical specifications by the engine. At the second stage using The CC fine-tuning was performed in order to optimize the performance by using CFD-calculation. At that the calculated method was used for which the verification has been performed by the bench tests. Such a CC fine-tuning allowed to reduce the product development period and improve its characteristics.

Multi-purpose high-performance micro-turbines

The article contains the results of development of small-size gas turbine engine with efficiency not lower than top piston engines. It is shown that use of a heat exchanger with an ultrahigh degree of regeneration (95% and above) in microturbines allows to raise the efficiency of small gas turbine engines up to 38-43%.

Performance Based Anomaly Detection Analysis of a Gas Turbine Engine by Artificial Neural Network Approach

This present work follows our earlier research efforts on fault diagnosis and prognosis solutions considering statistical and physics based approaches. In-service performance analysis and detection of any malfunctioning in an operating small sized gas turbine engine using artificial neural network approach is the central theme of this work. The measured engine operating and performance parameters are used to train two neural network models, namely back propagation and generalized regression. Following the training and validation of the neural network model, simulation results for test data corresponding to various engine usage stages are found to be close by two models. The analysis identifies an anamoly in the simulated and measured data collected 17 months after the engine overhauling which may be attributed to deliberate adjustments in the operating parameters. A threshold for anomaly detection in terms of the probability levels for variation of the rated power capacity of the engine is also studied.

발전용 소형가스터빈엔진 제어시스템 개발

Small-sized gas turbine engine could be applied to various fields such as propulsion, power generation, machine driving, etc., and Doosan has been developing 5MW class gas turbine engine for power generation since 2005. To verify its design performance and operating characteristics, a gas turbine engine test facility was constructed, and control system was also established to satisfy rapid and reliable control performance. In this paper, the hardware specification and structure of control system for gas turbine engine are introduced, and test result for starting characteristics analysis and loading is also presented.

상용 S/W를 이용한 소형가스터빈엔진 회전체의 동적 구조해석 및 검증

The accurate prediction of dynamic characteristics of high speed rotors, such as gas turbines, is important to avoid the possibility of operating the machinery near the critical speeds or unstable speed regions. However, the dynamic analysis methods and softwares for gas turbines have been developed in the process of producing many gas turbines by manufacturers and most of them have seldom been disclosed to the public. Recently, commercial FEM softwares, such as SAMCEF, ANSYS and NASTRAN, started supporting some rotordynamics analysis modules based on 3-D finite elements. In this paper, the dynamic analysis method using commercial S/W, especially ANSYS, is attempted for the small-size gas turbine engine rotor, and the analysis capability and limitations of its rotordyamics module are evaluated for further improvement of the module. As the preliminary procedure, the rotordyamic analysis capability of ANSYS was tested and evaluated with the reference models of the well-known dynamics. The limitations in application of the rotordynamics module were then identified. Under the current capability and limitations of ANSYS, it is shown that Lee diagram, a new frequency-speed diagram enhanced with the concept of <TEX>$H{\infty}$</TEX> in rotating machinery, can be indirectly obtained from FRFs computed from harmonic response analysis of ANSYS. Finally, it is demonstrated based on the modeling and analysis method developed in the process of the S/W verification that the conventional Campbell diagram, Lee diagram, mode shapes and critical speeds of the small-size gas turbine engine rotor can be computed using the ANSYS rotordynamics module.