Defect Detection in an Annular Swirl-Burner-Array by Optical Measuring Exhaust Gases

2016 ◽  
Author(s):  
Henrik von der Haar ◽  
Ulrich Hartmann ◽  
Christoph Hennecke ◽  
Friedrich Dinkelacker ◽  
Joerg R. Seume
Keyword(s):  
Power Distribution ◽  
Measurement Techniques ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
Maximum Output ◽  
Aircraft Engines ◽  
Combustion Chambers ◽  
Scaled Model ◽  
Ongoing Research ◽  
Exhaust Gases

Defects in combustion chambers of aircraft engines might have an impact on the reliability of the downstream turbine and the machine’s performance. Detecting failures in the combustion chamber of an aircraft engine during operation may improve the resource management and the availability of the system. Aim of the ongoing research project is to find an approach to evaluate the state of the jet engine by analyzing the temperature and emissions field in the exhaust jet. This investigation is part of the collaborative research center SFB 871. The SFB 871 deals with the improvement of the regeneration process of complex capital goods such as aircraft engines. Maintenance, repair, and overhaul processes would be more efficient if the internal status of the engine would be known while still on the wing before it is disassembled. The feasibility of this approach is investigated for a pilot scaled model combustor, which provides optical access and allows the selection of “defined errors” in the combustor. It consists of an atmospheric tubular combustor with an array of eight premixed swirl burners with a maximum output of 160 kW. The operating conditions of one of the eight burners concerning power and air-fuel ratio, can be controlled. A power distribution between the burners is typical fault in an aircraft combustor and will be investigated in this study. It is observed that it is possible to determine small deviations by measuring density profiles applying a tomographic background-oriented schlieren (BOS) technique behind the combustor. Additionally, particle image velocimetry is used to measure differences in the velocity field of the exhaust gases. This study shows that a minimum power deviation of one burner in an array of a total of eight burners is detectable in the exhaust plane with the above mentioned measurement techniques.

scholarly journals EXPERT STUDIES OF VIOLATIONS OF THE OPERATING CONDITIONS OF AUTOMOBILE ENGINES WHEN USING THEM IN AVIATION

2021 ◽  
pp. 53-59
Author(s):  
Alexander Khrulev ◽  
Iryna Saraievа
Keyword(s):  
Operating Time ◽  
Aircraft Engine ◽  
Point Of View ◽  
Operating Conditions ◽  
General Aviation ◽  
Aircraft Engines ◽  
Automobile Engine ◽  
Design Changes ◽  
Automobile Engines ◽  
Single Use

Problem. The features of the design and operation of piston engines in general aviation are considered. Comparative analysis of design features and parameters of automobile and aircraft engines is carried out. It is shown that car engines, despite the high technical level achieved at the beginning of the 21st century, do not technically meet aviation requirements. At the same time, engines created on the basis of automobiles through their deep modernization meet aviation requirements, however, modernization and adaptation of a standard automobile engine to aviation use in terms of costs compared to the creation of a new engine. Purpose. Carry out research on the failure of automobile engines used in light aviation. Methodology. Rough calculations of the service life of an automobile engine were made based on standard driving tests and a flight plan. According to the results of calculations, it has been established that the resource of a standard automobile engine in aviation is reduced many times due to prolonged operation at high loads and rotational speed that are not characteristic of ordinary automotive applications. Results. Experimental data have been obtained on the actual failure of standard automobile engines in aviation during the operating time, significantly less resource of aircraft engines of well-known brands. Based on the results of the study, it was concluded that the use of general aviation automobile engines is economically ineffective due to a short resource and insufficient reliability. Originality. Modern automobile engines, despite their technical perfection, cannot be used in aviation, since they do not correspond to aviation operating conditions. At the same time, adaptation of automobile engines to aviation applications is possible, but requires significant design changes, which makes their single use, as a rule, technically impractical and economically ineffective. Practical value. Due to the fact that saving on an aircraft engine is unacceptable from the point of view of flight safety, the aviation use of automobile engines without special modernization carries excessive risks of failures and their consequences. As a result, serial aircraft engines Lycoming, Continental, Jabiru, ULPower, Rotax, Limbach and others have virtually no alternative in general aviation.

scholarly journals Aircraft-engine particulate matter emissions from conventional and sustainable aviation fuel combustion: comparison of measurement techniques for mass, number, and size

2022 ◽  
Author(s):  
Joel C. Corbin ◽  
Tobias Schripp ◽  
Bruce E. Anderson ◽  
Greg J. Smallwood ◽  
Patrick LeClercq ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Volume Fraction ◽  
Geometric Mean ◽  
Measurement Techniques ◽  
Reference Value ◽  
Aircraft Engine ◽  
Aviation Fuel ◽  
Jet Fuels ◽  
Aircraft Engines ◽  
Laser Induced Incandescence

Abstract. Sustainable aviation fuels (SAFs) have different compositions compared to conventional petroleum jet fuels, particularly in terms of fuel sulphur and hydrocarbon content. These differences may change the amount and physicochemical properties of volatile and non-volatile particulate matter (nvPM) emitted by aircraft engines. In this study, we evaluate whether comparable nvPM measurement techniques respond similarly to nvPM produced by three blends of SAFs compared to three conventional fuels. Multiple SAF blends and conventional (Jet A-1) jet fuels were combusted in a V2527-A5 engine, while an additional conventional fuel (JP-8) was combusted in a CFM56-2C1 engine. We evaluated nvPM mass concentration measured by three real-time sampling techniques: photoacoustic spectroscopy, laser-induced incandescence, and the extinction-minus-scattering technique. Various commercial instruments were tested including three LII 300s, one PAX, one MSS+, and two CAPS PMSSA. Mass-based emission indices (EIm) reported by these techniques were similar, falling within 30 % of their geometric mean for EIm above 100 mg/kgfuel (approximately 10 μg PM m−3 at the instrument), this geometric mean was therefore used as a reference value. Additionally, two integrative measurement techniques were evaluated: filter photometry and particle size distribution (PSD) integration. The commercial instruments used were one TAP, one PSAP, and two SMPSs. These techniques are used in specific applications, such as on-board research aircraft to determine PM emissions at cruise. EIm reported by the alternative techniques fell within approximately 50 % of the mean aerosol-phase EIm. In addition, we measured PM-number-based emissions indices using PSDs and condensation particle counters. The commercial instruments used included TSI SMPSs, a Cambustion DMS500, and an AVL APC, and the data also fell within approximately 50 % of their geometric mean. The number-based emission indices were highly sensitive to the accuracy of the sampling-line penetration functions applied as corrections. In contrast, the EIm data were less sensitive to those corrections since a smaller volume fraction fell within the size range where corrections were substantial. A separate, dedicated experiment also showed that the operating laser fluence used in the LII 300 laser-induced incandescence instrument for aircraft engine nvPM measurement is adequate for a range of SAF blends investigated in this study. Overall, we conclude that all tested instruments are suitable for the measurement of nvPM emissions from the combustion of SAF blends in aircraft engines.

Experimental and Numerical Investigation of Different Flame Types Inside a Laboratory Scale RQL Combustion Chamber

2019 ◽  
Author(s):  
Thomas von Langenthal ◽  
Nikolaos Zarzalis ◽  
Marco Konle
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Thermal Power ◽  
Measurement Techniques ◽  
Flame Structure ◽  
Operating Conditions ◽  
Test Rig ◽  
Combustion Chambers ◽  
Primary Zone ◽  
Secondary Air

Abstract RQL (rich burn, quick quench, lean burn) combustion chambers are common in modern aero engines due to their low NOx emissions and good stability. The rich primary zone leads to lower flame temperatures and in combination with the lack of oxygen, the NOx production is low. The mixing of the secondary air must be quick in order to avoid stoichiometric conditions and at the same time must ensure the oxidation of the soot produced in the fuel rich primary zone to keep soot emissions to a minimum. However, the design of such a combustion chamber is complicated due to the complex interaction between the swirling primary flow and the jets of the secondary airflow. In this paper, we present a new test rig, which was designed to study combustion processes inside RQL combustion chambers at atmospheric conditions. The test rig features liquid kerosene combustion and a realistic quenching zone as well as good access for optical and conventional measurement techniques. For realistic engine like conditions the combustion air is preheated to 600 K and the fuel–air equivalence ratio in the primary combustion zone is set to be between Φ = 1.66 and Φ = 1.25, resulting in an overall thermal power between 80 kW and 110 kW. To get insights into the complex flow field inside the combustion chamber unsteady RANS simulations of both the reacting and the non-reacting case were performed using OpenFOAM. The turbulent flow field was modeled using the k-ω-SST model and the combustion was simulated using the Partially Stirred Reactor model. The experimental investigations showed two stable flame types for the same operating conditions with considerable differences in the visible flame structure and soot radiation. The flow field of both of these flame types were measured using a 1.5 kHz 2D PIV System. The numerical simulations showed good overall agreement with the experimental results but could not represent the change in flame type. In order to understand the underlying effects of the flame change the OH* chemiluminescence was recorded and the two-phase flow near the nozzle exit was investigated. This showed that the change in flame structure might arise due to spray dispersion of the pilot fuel nozzle and the recirculation of the secondary air into the primary zone.

scholarly journals Simulation of an aircraft radial engine misfire detection

2019 ◽  
Vol 87 ◽  
pp. 01011
Author(s):  
Łukasz Grabowski ◽  
Paweł Karpiński ◽  
Konrad Pietrykowski
Keyword(s):  
Engine Speed ◽  
Test Bench ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
Second Derivative ◽  
Aircraft Engines ◽  
Dimensional Model ◽  
Fluctuation Method ◽  
The Stability ◽  
Misfire Detection

The misfire phenomenon is particularly unfavourable in aircraft engines because it affects the stability and reliability of work. This paper presents the algorithm for detecting ignition failure in a radial aircraft engine. The Crankshaft Velocity Fluctuation method was applied, which consists in analysing changes in the crankshaft speed signal as a function of time. A zero-dimensional model of the aircraft engine was developed in order to perform the research. The validation of the model was performed using the results from the test bench. The model was subjected to simulation tests in fixed operating conditions. Based on the engine speed signal obtained as a result of the simulation, the normalized second derivative of the signal was determined based on the adopted algorithm. On the basis of this derivative, a criterion was defined to assess the occurrence of the misfire phenomenon. The results of the calculations can be compared in future with the results of the real engine tests.

scholarly journals Application of a Constant Gain Extended Kalman Filter for In-Flight Estimation of Aircraft Engine Performance Parameters

2005 ◽  
Author(s):  
Takahisa Kobayashi ◽  
Donald L. Simon ◽  
Jonathan S. Litt
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
Accurate Estimation ◽  
Aircraft Engines ◽  
Performance Parameters ◽  
Efficient Manner ◽  
Engine Operation ◽  
Engine Model

An approach based on the Constant Gain Extended Kalman Filter (CGEKF) technique is investigated for the in-flight estimation of non-measurable performance parameters of aircraft engines. Performance parameters, such as thrust and stall margins, provide crucial information for operating an aircraft engine in a safe and efficient manner, but they can not be directly measured during flight. A technique to accurately estimate these parameters is, therefore, essential for further enhancement of engine operation. In this paper, a CGEKF is developed by combining an on-board engine model and a single Kalman gain matrix. In order to make the on-board engine model adaptive to the real engine’s performance variations due to degradation or anomalies, the CGEKF is designed with the ability to adjust its performance through the adjustment of artificial parameters called “tuning parameters.” With this design approach, the CGEKF can maintain accurate estimation performance when it is applied to aircraft engines at off-nominal conditions. The performance of the CGEKF is evaluated in a simulation environment using numerous component degradation and fault scenarios at multiple operating conditions.

scholarly journals A New Method of Calculating the Attainable Life and Reliability in Aerospace Bearings

2020 ◽  
Vol 5 (6) ◽  
pp. 745-750
Author(s):  
Peter Gloeckner ◽  
W. Sebald
Keyword(s):  
Gas Turbines ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
New Method ◽  
Aviation Industry ◽  
Flight Safety ◽  
Rolling Element Bearings ◽  
Aircraft Engines ◽  
Increased Risk ◽  
Rolling Element

The aviation industry made significant progress improving reliability, efficiency and performance throughout the last decades. Especially aircraft engines and helicopter transmission systems contributed significantly to these improvements. The kerosene consumption decreased by 70 % and the CO2 emissions due to air transport decreased by 30 % per passenger kilometer within the last 20 years. Simultaneously, the flight safety was increased with aircraft engine in-flight-shut-downs as low as 1 ppm and „unscheduled engine removals” as low as 4 ppm. Flight safety is equal to the reliability of the systems in service. Failure of these systems directly leads to exposure of human life. Among the most critical aviation systems are aircraft engines including the rolling element bearings which support the rotors. A serious damage to the aircraft engine main shaft bearings during flight requires shout-down of the engine to avoid a further damage escalation subsequently leading to engine fire. Today, it is a requirement for aircraft to operate with one engine shut down. However, each in-flight-engine-shut-down typically is connected with flight diversion or abort and immediate landing. Inflight-shut-downs translate into increased risk for passengers and crew and substantial on cost. Therefore, rolling element bearings for aircraft engines are developed – similar to other aircraft engine components – targeting a reliability of nearly 100 % over an operation time of more than 10 000 hours prior to overhaul. To achieve this requirement despite the extreme operating conditions such as high speed and temperatures occurring in gas turbines, special high-performance materials are used for the rolling bearing components which are partially integrated in surrounding engine parts like shafts and housings. These special conditions - deviating from conventional industrial rolling element bearing applications - are currently not sufficiently considered in the standardized method of calculating the bearing life per ISO 281. A new method of calculating the attainable life of rolling elements bearing in aerospace applications is presented. This method considers the special aerospace conditions and materials and thus enables a higher reliability of the theoretical analysis and life prediction.

Validation of mathematical model of electrothermal calculation of DC catenary on the basis of scale model

2018 ◽  
Vol 77 (4) ◽  
pp. 222-229 ◽  
Author(s):  
A. V. Paranin ◽  
A. B. Batrashov
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Scale Model ◽  
Contact Network ◽  
Scaled Model ◽  
Cross Sectional ◽  
Current Collection ◽  
Topological Features ◽  
Study Results ◽  
Real Physical Process

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

scholarly journals Optimal Tuner Selection for Kalman Filter-Based Aircraft Engine Performance Estimation

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Donald L. Simon ◽  
Sanjay Garg
Keyword(s):  
Kalman Filter ◽  
Estimation Error ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Experimental Simulation ◽  
Tuning Parameter ◽  
Estimation Accuracy ◽  
On Line

A linear point design methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented. This technique specifically addresses the underdetermined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multivariable iterative search routine that seeks to minimize the theoretical mean-squared estimation error. This paper derives theoretical Kalman filter estimation error bias and variance values at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared with the conventional approach of tuner selection. Experimental simulation results are found to be in agreement with theoretical predictions. The new methodology is shown to yield a significant improvement in on-line engine performance estimation accuracy.

scholarly journals Organic Rankine cycle for turboprop engine application

2021 ◽  
pp. 1-21
Author(s):  
G.E. Pateropoulos ◽  
T.G. Efstathiadis ◽  
A.I. Kalfas
Keyword(s):  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Weight Ratio ◽  
Rankine Cycle ◽  
Aircraft Engine ◽  
Working Fluid ◽  
Engine Fuel ◽  
Exhaust Gases ◽  
Waste Heat Recovery System ◽  
Turboprop Engine

ABSTRACT The potential to recover waste heat from the exhaust gases of a turboprop engine and produce useful work through an Organic Rankine Cycle (ORC) is investigated. A thermodynamic analysis of the engine’s Brayton cycle is derived to determine the heat source available for exploitation. The aim is to use the aircraft engine fuel as the working fluid of the organic Rankine cycle in order to reduce the extra weight of the waste heat recovery system and keep the thrust-to-weight ratio as high as possible. A surrogate fuel with thermophysical properties similar to aviation gas turbine fuel is used for the ORC simulation. The evaporator design as well as the weight minimisation and safety of the suggested application are the most crucial aspects determining the feasibility of the proposed concept. The results show that there is potential in the exhaust gases to produce up to 50kW of power, corresponding to a 10.1% improvement of the overall thermal efficiency of the engine.

scholarly journals A Flexible Load Control Strategy for Distribution Network to Reduce the Line Losses and to Eliminate the Transmission Congestion

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Beibei Wang ◽  
Xiaoqing Hu ◽  
Peifeng Shen ◽  
Wenlu Ji ◽  
Yang Cao ◽  
...  
Keyword(s):  
Power Distribution ◽  
Distribution Systems ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Test System ◽  
Operating Conditions ◽  
Load Control ◽  
Transmission Congestion ◽  
Heavy Load ◽  
Flexible Load

There are many uncertain factors in the modern distribution network, including the access of renewable energy sources and the heavy load level. The existence of these factors has brought challenges to the stability of the power distribution network, as well as increasing the risk of exceeding transmission capacity of distribution lines. The appearance of flexible load control technology provides a new idea to solve the above problems. Air conditioners (ACs) account for a great proportion of all loads. In this paper, the model of dispatching AC loads in the regional power grid is constructed, and the direct load control (DLC) method is adopted to reduce the load of ACs. An improved tabu search technique is proposed to solve the problem of network dispatch in distribution systems in order to reduce the resistive line losses and to eliminate the transmission congestion in lines under normal operating conditions. The optimal node solution is obtained to find the best location and reduction capacity of ACs for load control. To demonstrate the validity and effectiveness of the proposed method, a test system is studied. The numerical results are also given in this article, which reveal that the proposed method is promising.

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