Hybrid Method Based on FV Concept for Lean Blowout Limits Predictions for Aero Engine Combustors With Low Inlet Temperature

2020 ◽  
Author(s):  
Sun Lei ◽  
Huang Yong ◽  
Feng Xiang
Keyword(s):  
Low Temperature ◽  
High Altitude ◽  
Hybrid Method ◽  
Prediction Models ◽  
Inlet Temperature ◽  
Lean Blowout ◽  
Aero Engine ◽  
Flight Envelope ◽  
Aero Engines ◽  
Additional Equation

Abstract Lean blowout (LBO) limit is one of the most important parameters for aero engines. The LBO must be avoided during the whole flight envelope and modes. Thus the LBO limit should be predicted accurately during the research and development (R&D) process of an aero engine combustor. Some prediction models had been proposed by the previous studies. Lefebvre’s LBO model is widely used among these models due to its good accuracy and generality. Based on Lefebvre’s LBO model, the flame volume (FV) model is proposed to improve the prediction accuracy as well as keep the good generality. However, an additional equation is needed when the FV model is applied to predict the LBO limit. Based on our previous studies, the volume in the combustor liner enclosed by the iso-surface whose temperature is 900K could be chosen as the flame volume. The flame volume could be served as the additional equation and further makes the FV model available for the LBO limit prediction. This method could be named as the hybrid method based on the FV concept in this paper. On the other hand, the LBO limit at high altitude is attracting more and more attentions due to the extension of the flight envelope and modes in the recent years. Low inlet temperature is one of the most typical characteristics for the operating condition at high altitude. The temperature could reach less than −40 °C at high altitude. Compared with the normal condition, the characteristics of flow, atomization and combustion are different at the low temperature condition. In this paper, the hybrid method based on the FV concept is applied to predict the LBO limits of 11 combustors with low inlet temperature. The inlet temperature is 236.2K (corresponding to the altitude of 8km). The results show that the flame volumes obtained by the numerical simulation vary near linearly with the fuel/air ratio when the fuel/air ratio is close to the LBO limits. For all these 11 combustor configurations, the LBO limits with low inlet temperature (236.2K) obtained from the hybrid method based on the FV concept are significantly larger than those with normal inlet temperature (300K) obtained from experiments. The maximum and minimum increases are 29% and 2%, respectively. The LBO limits increases are more than 20% and 10% for 6 out of the 11 combustors and 9 out of the 11 combustors, respectively. The reasons for the increase of the LBO limits at low temperature include the decreasing of chemical reaction rate and evaporation rate, the increasing of the mean drop size.

Performance Research on the High-Altitude Valve of an Aero-Engine Ventilation System

2011 ◽  
Vol 138-139 ◽  
pp. 540-547
Author(s):  
Li Chao Su ◽  
Zhen Xia Liu ◽  
Ya Guo Lu
Keyword(s):  
High Altitude ◽  
Ventilation System ◽  
Experimental Tests ◽  
Static Characteristic ◽  
Relational Information ◽  
Improve Design ◽  
Operation Process ◽  
Aero Engine ◽  
Aero Engines ◽  
Performance Research

For aero-engines, high-altitude valve is a key component, which is important to the high-altitude performance of ventilation system. However, theoretical researches or experimental tests of high-altitude valve are rare. To define whether the high-altitude valve can work normally during the whole flight envelope and to offer relational information for the improve design, this article focuses on the operation process and characteristic computation of high-altitude valve. Based on operational principle and structural analysis, using mechanics method, the high-altitude characteristic computation of high-altitude valve was done and the flight height where the valve closes was identified. In the same way, we analysed the static characteristic, getting the inner-cavity pressure in high-altitude flying state. Compared with the experimental results, the analytical methods and calculated values are validated to be accurate. The characteristic curves obtained can be directly used in the check and acceptance or further design of high-altitude valve.

scholarly journals Hybrid method based on flame volume concept for lean blowout limits prediction of aero engine combustors

2021 ◽  
Vol 34 (5) ◽  
pp. 425-437
Author(s):  
Lei SUN ◽  
Yong HUANG ◽  
Xiwei WANG ◽  
Zekun ZHENG ◽  
Ruixiang WANG ◽  
...  
Keyword(s):  
Hybrid Method ◽  
Lean Blowout ◽  
Aero Engine

Basic Research of the Intercooled Turbofan Aero-Engine

2012 ◽  
Vol 516-517 ◽  
pp. 544-547
Author(s):  
Jin Chuan Zhang ◽  
Yun Wang ◽  
Can Zhang
Keyword(s):  
Pressure Ratio ◽  
Basic Research ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Gas Temperature ◽  
High Pressure Compressor ◽  
Aero Engine ◽  
Aero Engines ◽  
Cooling Air ◽  
Aircraft Application

In conventional turbofan aero-engine designs, the effective way of improvement of engine efficiency is through the increasing of overall pressure ratio and improving of combustor inlet gas temperature, but the further incresement of compressor overall pressor ratio is constricted by high pressure compressor outlet allowed temperature. The improvement of combustor outlet temperature is limited by turbine allowed inlet temperature during take-off and climbing. An intercooled core can be designed with a significantly higher overall pressure ratio also with reduced cooling air requirements, providing a higher thermal efficiency compared with a conventional core. Through the basic analysis of performance of intercooler aeroengines. It indicated that the intercooled aero-engines can decrese the feul consume clearly and have a further potential in future civil aircraft application.

scholarly journals Performance analysis of an aero engine with inter-stage turbine burner

2017 ◽  
Vol 121 (1245) ◽  
pp. 1605-1626 ◽  
Author(s):  
F. Yin ◽  
A. Gangoli Rao
Keyword(s):  
Fuel Consumption ◽  
Thermal Efficiency ◽  
Pressure Ratio ◽  
Future Generation ◽  
Nox Emission ◽  
Inlet Temperature ◽  
Performance And Emission ◽  
Aero Engine ◽  
Aero Engines ◽  
Bypass Ratio

ABSTRACTThe historical trends of reduction in fuel consumption and emissions from aero engines have been mainly due to the improvement in the thermal efficiency, propulsive efficiency and combustion technology. The engine Overall Pressure Ratio (OPR) and Turbine Inlet Temperature (TIT) are being increased in the pursuit of increasing the engine thermal efficiency. However, this has an adverse effect on engine NOx emission. The current paper investigates a possible solution to overcome this problem for future generation Very High Bypass Ratio (VHBR)/Ultra High Bypass Ratio (UHBR) aero-engines in the form of an Inter-stage Turbine Burner (ITB). The ITB concept is investigated on a next generation baseline VHBR aero engine to evaluate its effect on the engine performance and emission characteristics for different ITB energy fractions. It is found that the ITB can reduce the bleed air required for cooling the HPT substantially (around 80%) and also reduce the NOx emission significantly (>30%) without penalising the engine specific fuel consumption.

Unsteady simulations of migration and deposition of fly-ash particles in the first-stage turbine of an aero-engine

2021 ◽  
pp. 1-21
Author(s):  
Z. Hao ◽  
X. Yang ◽  
Z. Feng
Keyword(s):  
Fly Ash ◽  
Film Cooling ◽  
Particle Deposition ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Velocity Model ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Aero Engine

Abstract Particulate deposits in aero-engine turbines change the profile of blades, increase the blade surface roughness and block internal cooling channels and film cooling holes, which generally leads to the degradation of aerodynamic and cooling performance. To reveal particle deposition effects in the turbine, unsteady simulations were performed by investigating the migration patterns and deposition characteristics of the particle contaminant in a one-stage, high-pressure turbine of an aero-engine. Two typical operating conditions of the aero-engine, i.e. high-temperature take-off and economic cruise, were discussed, and the effects of particle size on the migration and deposition of fly-ash particles were demonstrated. A critical velocity model was applied to predict particle deposition. Comparisons between the stator and rotor were made by presenting the concentration and trajectory of the particles and the resulting deposition patterns on the aerofoil surfaces. Results show that the migration and deposition of the particles in the stator passage is dominated by the flow characteristics of fluid and the property of particles. In the subsequential rotor passage, in addition to these factors, particles are also affected by the stator–rotor interaction and the interference between rotors. With higher inlet temperature and larger diameter of the particle, the quantity of deposits increases and the deposition is distributed mainly on the Pressure Side (PS) and the Leading Edge (LE) of the aerofoil.

Aero-engine dynamic model based on an improved compact propulsion system dynamic model

2021 ◽  
pp. 095965182098408
Author(s):  
Qiangang Zheng ◽  
Yong Wang ◽  
Chongwen Jin ◽  
Haibo Zhang
Keyword(s):  
Dynamic Model ◽  
Propulsion System ◽  
System Dynamic ◽  
Inlet Temperature ◽  
System Dynamic Model ◽  
Component Level ◽  
Engine Model ◽  
Surge Margin ◽  
Aero Engine ◽  
Engine Dynamic

The modern advanced aero-engine control methods are onboard dynamic model–based algorithms. In this article, a novel aero-engine dynamic modeling method based on improved compact propulsion system dynamic model is proposed. The aero-engine model is divided into inlet, core engine, surge margin and nozzle models for establishing sub-model in the compact propulsion system dynamic model. The model of core engine is state variable model. The models of inlet, surge margin and nozzle are nonlinear models which are similar to the component level model. A new scheduling scheme for basepoint control vector, basepoint state vector and basepoint output vector which considers the change of engine total inlet temperature is proposed to improve engine model accuracy especially the steady. The online feedback correction of measurable parameters is adopted to improve the steady and dynamic accuracy of model. The modeling errors of improved compact propulsion system dynamic model remain unchanged when engine total inlet temperature of different conditions are the same or changes small. The model accuracy of compact propulsion system dynamic model, especially the measurable parameters, is improved by online feedback correction. Moreover, the real-time performance of compact propulsion system dynamic model and improved compact propulsion system dynamic model are much better than component level model.

scholarly journals Aero-Engine Fault Diagnosis Using Improved Local Discriminant Bases and Support Vector Machine

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jianwei Cui ◽  
Mengxiao Shan ◽  
Ruqiang Yan ◽  
Yahui Wu
Keyword(s):  
Support Vector Machine ◽  
Fault Diagnosis ◽  
Wavelet Packet ◽  
Energy Difference ◽  
Test System ◽  
Support Vector ◽  
Svm Classifier ◽  
Aero Engine ◽  
Aero Engines ◽  
Optimal Set

This paper presents an effective approach for aero-engine fault diagnosis with focus on rub-impact, through combination of improved local discriminant bases (LDB) with support vector machine (SVM). The improved LDB algorithm, using both the normalized energy difference and the relative entropy as quantification measures, is applied to choose the optimal set of orthogonal subspaces for wavelet packet transform- (WPT-) based signal decomposition. Then two optimal sets of orthogonal subspaces have been obtained and the energy features extracted from those subspaces appearing in both sets will be selected as input to a SVM classifier to diagnose aero-engine faults. Experiment studies conducted on an aero-engine rub-impact test system have verified the effectiveness of the proposed approach for classifying working conditions of aero-engines.

Low Order Modeling for Fan and Outlet Guide Vanes in Aero-Engines

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Jiahuan Cui ◽  
Rob Watson ◽  
Yunfei Ma ◽  
Paul Tucker
Keyword(s):  
Detailed Analysis ◽  
Immersed Boundary Method ◽  
Low Cost ◽  
Immersed Boundary ◽  
Test Case ◽  
Guide Vanes ◽  
Compression System ◽  
Aero Engine ◽  
Aero Engines ◽  
Low Order

Intakes of reduced length have been proposed with the aim of producing aero-engines with higher efficiency and reduced weight. As the intake length decreases, it is expected that stronger effects of the fan on the flow over the intake lip will be seen. If the effects of the fan cannot be ignored, a low-cost but still accurate fan model is of great importance for designing a short-intake. In this paper, a low order rotor/stator model, the immersed boundary method with smeared geometry (IBMSG), has been further developed and validated on a rig test case. The improved IBMSG is more robust than the original. The rig test case used for validation features a low-pressure compression system with a nonaxisymmetric inflow, which is representative of the inlet condition of an aero-engine at its cruise condition. Both the fan and the outlet guide vanes (OGVs) are modeled using IBMSG. A detailed analysis is carried out on the flow both upstream and downstream of the fan. After validating the IBMSG method against the rig test case, a short-intake case, coupled with a fan designed for the next generation of aero-engines, is further investigated. It is found that compared with the intake-alone case, the inflow distortion at the fan face is significantly reduced by the presence of fan. Due to this increased interaction between the fan and the flow over the intake lip, accounting for the effects of the downstream fan is shown to be essential when designing a short intake.

Modern Methods of Testing Aero-Engines and Power Plants

1950 ◽  
Vol 54 (474) ◽  
pp. 327-358 ◽  
Author(s):  
A. C. Lovesey
Keyword(s):  
Power Plants ◽  
Test Equipment ◽  
Flow Meter ◽  
Fuel Flow ◽  
Modern Methods ◽  
Aero Engine ◽  
Aero Engines

In the early days of aero-engines the test equipment was limited to little more than a brake or dynamometer, a fuel flow meter and a few thermometers, and the development of these engines in the direction of better performance and reliability, to a large extent, was an art, built up of experience aided by instinct, of deducing the happenings inside an engine from the few meagre measurements obtainable.Nevertheless, the aero-engine made healthy progress, became more complicated in the process, and introduced many more problems.

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