A Preliminary Design Tradeoff Study for an Advanced Propulsion Technology Rotorcraft at Mission Level

Author(s):  
Fakhre Ali ◽  
Ioannis Goulos ◽  
Vassilios Pachidis

This paper aims to present an integrated rotorcraft (RC) multidisciplinary simulation framework, deployed for the comprehensive assessment of combined RC–powerplant systems at mission level. The proposed methodology comprises a wide-range of individual modeling theories applicable to RC performance and flight dynamics, as well as the gas turbine engine performance. The overall methodology has been deployed to conduct a preliminary tradeoff study for a reference simple cycle (SC) and conceptual regenerative twin-engine-light (TEL) and twin-engine-medium (TEM) RC configurations, modeled after the Airbus Helicopters Bo105 and Aérospatiale SA330 models, simulated under the representative mission scenarios. The installed engines corresponding to both reference RC are notionally modified by incorporating a heat exchanger (HE), enabling heat transfer between the exhaust gas and the compressor delivery air to the combustion chamber. This process of preheating the compressor delivery air prior to combustion chamber leads to a lower fuel input requirements compared to the reference SC engine. The benefits arising from the adoption of the on-board HE are first presented by conducting part-load performance analysis against the reference SC engine. The acquired results suggest substantial reduction in specific fuel consumption (SFC) for a major part of the operating power range with respect to both RC configurations. The study is further extended to quantify mission fuel burn (MFB) saving limit by conducting an extensive HE tradeoff analyses at mission level. The optimum fuel burn saving limit resulting from the incorporation of on-board HEs is identified within realistically defined missions, corresponding to modern RC operations. The acquired results from the mission analyses tradeoff study suggest that the suboptimum regenerated RC configurations are capable of achieving significant reduction in MFB, while simultaneously maintaining the respective airworthiness requirements in terms of one-engine-inoperative. The proposed methodology can effectively be regarded as an enabling technology for the comprehensive assessment of conventional and conceptual RC–powerplant systems at mission level.

Author(s):  
K. Karamolegkos ◽  
I. Goulos ◽  
V. Pachidis ◽  
J. Stevens ◽  
C. Smith ◽  
...  

This paper describes the work done and strong interaction between the Technology Evaluator (TE), Green Rotorcraft (GRC) Integrated Technology Demonstrator (ITD) and Sustainable and Green Engine (SAGE) ITD of the Clean Sky Joint Technology Initiative (JTI). The GRC and SAGE ITDs are responsible for developing new helicopter airframe and engine technologies respectively, whilst the TE has the distinctive role of assessing the environmental impact of these technologies at single flight (mission), airport and Air Transport System levels (ATS). The assessments reported herein have been performed by using a GRC-developed multidisciplinary simulation framework called PhoeniX (Platform Hosting Operational and Environmental Investigations for Rotorcraft) that comprises various computational modules. These modules include a rotorcraft performance code (EUROPA), an engine performance and emissions simulation tool (GSP) and a noise prediction code (HELENA). PhoeniX can predict the performance of a helicopter along a prescribed 4D trajectory offering a complete helicopter mission analysis. In the context of the TE assessments reported herein, two helicopter classes are examined namely a Twin Engine Light (TEL) configuration for Emergency Medical Service (EMS) and Police missions and a Single Engine Light (SEL) configuration for Passenger/Transport missions. The different technologies assessed reflect three simulation points which are the ‘Baseline’ Year 2000 technology, ‘Reference’ Y2020 technology, without Clean Sky benefits, and finally the ‘Conceptual’, reflecting Y2020 technology with Clean Sky benefits. The results of this study illustrate the potential that incorporated technologies possess in terms of improving performance and gas emission metrics such as fuel burn, CO2, NOx as well as the noise footprint on the ground.


Author(s):  
P. A. Phillips ◽  
Peter Spear

After briefly summarizing worldwide automotive gas turbine activity, the paper analyses the power plant requirements of a wide range of vehicle applications in order to formulate the design criteria for acceptable vehicle gas turbines. Ample data are available on the thermodynamic merits of various gas turbine cycles; however, the low cost of its piston engine competitor tends to eliminate all but the simplest cycles from vehicle gas turbine considerations. In order to improve the part load fuel economy, some complexity is inevitable, but this is limited to the addition of a glass ceramic regenerator in the 150 b.h.p. engine which is described in some detail. The alternative further complications necessary to achieve satisfactory vehicle response at various power/weight ratios are examined. Further improvement in engine performance will come by increasing the maximum cycle temperature. This can be achieved at lower cost by the extension of the use of ceramics. The paper is intended to stimulate the design application of the gas turbine engine.


2015 ◽  
Vol 119 (1211) ◽  
pp. 67-90 ◽  
Author(s):  
F. Ali ◽  
I. Goulos ◽  
V. Pachidis

AbstractThis paper aims to present an integrated multidisciplinary simulation framework, deployed for the comprehensive assessment of combined helicopter–powerplant systems at mission level. Analytical evaluations of existing and conceptual regenerative engine designs are carried out in terms of operational performance and environmental impact. The proposed methodology comprises a wide-range of individual modeling theories applicable to helicopter flight dynamics, gas turbine engine performance as well as a novel, physics-based, stirred reactor model for the rapid estimation of various helicopter emissions species. The overall methodology has been deployed to conduct a preliminary trade-off study for a reference simple cycle and conceptual regenerative twin-engine light helicopter, modeled after the Airbus Helicopters Bo105 configuration, simulated under the representative mission scenarios. Extensive comparisons are carried out and presented for the aforementioned helicopters at both engine and mission level, along with general flight performance charts including the payload-range diagram. The acquired results from the design trade-off study suggest that the conceptual regenerative helicopter can offer significant improvement in the payload-range capability, while simultaneously maintaining the required airworthiness requirements. Furthermore, it has been quantified through the implementation of a representative case study that, while the regenerative configuration can enhance the mission range and payload capabilities of the helicopter, it may have a detrimental effect on the mission emissions inventory, specifically for NOx(Nitrogen Oxides). This may impose a trade-off between the fuel economy and environmental performance of the helicopter. The proposed methodology can effectively be regarded as an enabling technology for the comprehensive assessment of conventional and conceptual helicopter-powerplant systems, in terms of operational performance and environmental impact as well as towards the quantification of their associated trade-offs at mission level.


2019 ◽  
Vol 18 (2) ◽  
pp. 52-61
Author(s):  
A. V. Grigoriev ◽  
A. A. Kosmatov ◽  
О. A. Rudakov ◽  
A. V. Solovieva

The article substantiates the necessity of designing an optimal gas generator of a gas turbine engine. The generator is to provide coordinated joint operation of its units: compressor, combustion chamber and compressor turbine with the purpose of reducing the period of development of new products, improving their fuel efficiency, providing operability of the blades of a high-temperature cooled compressor turbine and meeting all operational requirements related to the operation of the optimal combustion chamber including a wide range of stable combustion modes, high-altitude start at subzero air and fuel temperature conditions and prevention of the atmosphere pollution by toxic emissions. Methods of optimizing the parameters of coordinated joint operation of gas generator units are developed. These parameters include superficial flow velocities in the boundary interface cross sections between the compressor and the combustion chamber, as well as between the combustion chamber and the compressor turbine. The effective efficiency of the engine thermodynamic cycle is the optimization target function. The required depth of the turbine blades cooling is a functional constraint evaluated with account for calculations of irregularity and instability of the gas temperature field and the actual flow turbulence intensity at the blades’ inlet. We carried out theoretical analysis of the influence of various factors on the gas flow that causes changes in the flow total pressure in the channels of the gas generator gas dynamic model, i.e. changes in the efficiencies of its units. It is shown that the long period (about five years) of the engine final development time, is due to the necessity to perform expensive full-scale tests of prototypes, in particular, it is connected with an incoordinate assignment in designing the values of the flow superficial velocities in the boundary sections between the gas generator units. Designing of an optimal gas generator is only possible on the basis of an integral mathematical model of an optimal combustion chamber.


Author(s):  
Ali Fakhre ◽  
Vassilios Pachidis ◽  
Ioannis Goulos ◽  
Mahmood Tashfeen ◽  
Pericles Pilidis

The aim of the study presented in this paper, is to compare helicopters employing simple cycle turboshaft engines, with helicopters employing novel regenerated turboshafts. Two existing helicopter configurations, a Twin Engine Light and a Twin Engine Medium are compared against regenerated configurations. The reference installed engines of both helicopters are notionally optimized by incorporating a heat exchanger, which enables heat transfer between the exhaust gas and the compressor delivery air to the combustion chamber. This process leads to a lower fuel input requirement as well as higher overall thermal efficiency compared to the reference simple cycle engine. The benefits arising from the adoption of the heat exchanger for both configurations are firstly presented by conducting part-load performance analysis for each optimized engine against its reference simple cycle engine. The obtained results suggest substantial reduction in specific fuel consumption for a major part of the operating power range with respect to both helicopter configurations. The results also demonstrate that the heat exchanger effectiveness is a critical parameter in achieving further reductions in specific fuel consumption. The study is further extended to investigate mission fuel burn saving limits for both helicopter configurations under the simulated part-load performance conditions by conducting a heat exchanger tradeoff study. The weight estimation correlation for the heat exchanger is adopted from the previously reported studies of similar fashion and is simulated accordingly for both helicopter configurations. A multi-disciplinary simulation tool with an integrated range of capabilities applicable to helicopter performance evaluation and mission analysis is adopted to simulate various types of missions, targeting wide range of helicopter operations. The results of the mission analysis suggest that the regenerated counterpart configurations are capable of achieving significant reductions in mission fuel burn. However, the level of gain from mission fuel burn savings is dependent on the selected helicopter mission profile, the recuperator design effectiveness as well as the overall evaluation criteria. The results also conclude that while the amount of benefit is dependent on various parameters, there is always an optimum “saving” region for each mission that justifies the need for regeneration.


Author(s):  
A. V. Sudarev ◽  
Y. I. Zakharov ◽  
E. D. Vlnogradov ◽  
L. S. Butovsky ◽  
E. A. G. Ranovskaya

Initial results of the first step (at Pa = 0.11–0.12 MPa) of an experimental investigation of the basic parameters of full-scale, micro-flame double-zone combustors with flame tubes are presented. This combustion chamber is developed for a 2.5 MW advanced ceramic gas turbine unit. (Sudarev, et al., 1991). This engine, when working at the design operation conditions, has an efficiency range of 41–46%, which is a function of using either intecooling or a heat regeneration scheme. The efficiency is the result of increasing the gas temperature to a maximum turbine inlet temperature of 1250°C and a 2.5 MW pressure ratio of 29. With such high initial parameters of the working media, the problem of nitrogen oxide emissions reduction assumes paramount importance. The objective of the paper is to develop a combustor which would ensure NOx emissions at the design conditions not above 75 mg/Nm3 (at 15% 02) due to application of a double-stage working process of pre-mixture firing. Specific features of fuel burn-up, formation of pollutants at combustion, dependencies of combustor characteristics and upgraded algorithm of combustor loading are also shown.


2019 ◽  
Vol 18 (3) ◽  
pp. 81-98
Author(s):  
L. A. Magerramova ◽  
Yu. A. Nozhnitsky ◽  
S. A. Volkov ◽  
M. E. Volkov ◽  
V. Zh. Chepurnov ◽  
...  

The possibility of reducing the weight, simplifying the design, reducing the time and cost of development, production and operation are important advantages in the implementation of additive technologies (AT). The use of AT can significantly improve fuel efficiency, environmental and other characteristics of aircraft engines. The possibility of using AT in the production of various parts and components of engines is being currently investigated at CIAM. Examples of these developments, advantages of the use of AT and problems arising in the implementation of these technologies are presented in this article. Models of turbine blades with a highly efficient cooling system, in particular, with penetration cooling were designed and manufactured using optimization methods and taking into account the capabilities of AT. The possibilities of using AT for the manufacture of elements of molds for precision casting of gas turbine engine (GTE) blades of heat-resistant alloys and ceramic rods are shown. Elements of a two-zone front module of the low-emission combustion chamber of an advanced GTE are designed and manufactured using the AT method. Research of prospective branched tree channels of heat exchangers with mutually porous bodies that can be made only by AT methods and the use of which will make it possible to increase the efficiency of heat exchange in the case of lower weight, than that of the structures made by traditional technologies, is being carried out. The AT was used to manufacture complex elements of a ramjet engine. Fire tests of printed sections of the combustion chamber were carried out successfully. Cellular structures to be used in gas turbine engine parts with the aim of reducing their weight were developed. A hollow blade model with cellular-type core was made using AT. Tests of the designed cellular prototypes were carried out. The possibilities of reducing the mass of structural elements using cellular structures obtained by AT methods are shown. Research of hollow disks of turbines and other engine components produced with the aid of AT are carried out. Despite the fact that experimental studies of structural elements obtained by additive technologies have not been completed yet, these works show the prospects for the use of AT in the development of a wide range of engine parts and components.


Author(s):  
Nqobile Khani ◽  
Clara Segovia ◽  
Rukshan Navaratne ◽  
Vishal Sethi ◽  
Riti Singh ◽  
...  

A mechanical device such as an aircraft gas turbine engine will in its lifetime of service show the effects of damage and deterioration. The damage to (and deterioration of) an engine has an adverse effect on the engine’s overall performance. It is therefore vitally important to predict the effects of deterioration on the performance of an engine and on the economic (fuel burn and engine life) implications from an operator’s perspective. Engine component degradation leads to performance deterioration and change, which requires the engine to run hotter and faster so as to meet the required thrust and aircraft performance. Increasing engine operating temperatures and engine speed result in increased creep and fatigue damage to the hot section components and increases the engine life cycle costs. One way of reducing life cycle costs is by better usage of the engine and involves being certain about the life potential of the engine and its components and how this life evolves with use. A sound understanding of how the engine life evolves and to predict remaining life requires understanding the engine’s operating environment and how component damage is sustained and accumulated. Knowledge about the engine condition and the likely stresses to which it will be subjected is required to analyse engine component usage and reduce degradation, raise safe-life limits of components and reduce maintenance requirements. This paper lays the foundation for the development of a prognostic tool that will capture and model the mechanisms of degradation, and predict levels of degradation based on engine deployment. The mechanisms that will cause degradation are assessed and integrated to establish the requirements of the tool. The paper discusses how degradation will affect component and engine performance and also the life of the engine.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Michal Folusiak ◽  
Karol Swiderski ◽  
Piotr Wolański

AbstractThe idea of using the phenomenon of rotating detonation to propulsion has its roots in fifties of the last century in works of Adamson et al. and Nicholls et al. at the University of Michigan. The idea was recently reinvented and experimental research and numerical simulations on the Rotating Detonation Engine (RDE) are carried in numerous institutions worldwide, in Poland at Warsaw University of Technology (WUT) since 2004. Over the period 2010-2014 WUT and Institute of Aviation (IOA) jointly implemented the project under the Innovative Economy Operational Programme entitled ‘Turbine engine with detonation combustion chamber’. The goal of the project was to replace the combustion chamber of turboshaft engine GTD-350 with the annular detonation chamber.This paper is focused on investigation of the influence of a geometry and flow conditions on the structure and propagation stability of the rotating detonation wave. Presented results are in majority an outcome of the aforementioned programme, in particular authors’ works on the development of the in-house code REFLOPS USG and its application to simulation of the rotating detonation propagation in the RDE.


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