scholarly journals Investigations of the temperature distribution in the exhaust system of an aircraft piston engine

2019 ◽  
Vol 177 (2) ◽  
pp. 12-18
Author(s):  
Jacek CZARNIGOWSKI ◽  
Krzysztof SKIBA ◽  
Kamil DUBIEŃSKI
Keyword(s):  
Temperature Distribution ◽  
Engine Speed ◽  
Exhaust System ◽  
Heat Emission ◽  
Piston Engine ◽  
Engine Operation ◽  
Bench Tests ◽  
Exhaust Gases ◽  
Engine Cooling ◽  
Wide Range

Ultralight aviation is based on piston engines requiring both performance and reliability. An important aspect is also the require-ments for the installation of such an engine on an airframe, especially its heat emission. This is firstly because of the need to ensure proper engine cooling and secondly because composite elements of the airframe skin are not exposed to excessive overheating. For this purpose, bench tests of the temperature distribution of the exhaust system of ROTAX 912 engine were carried out. Measurements were taken at 6 points of the exhaust system, where the temperature of the exhaust gases and exhaust pipes were measured. The tests covered a wide range of engine operation. The paper presents the temperature distribution at selected points in relation to the engine speed and load.

OPTIMIZATION OF GAS-DIESEL ENGINE REGULATION AS A METHOD OF IMPROVING ITS ECOLOGICAL CHARACTERISTICS

2021 ◽  
pp. 28-32
Author(s):  
VALERIY L. CHUMAKOV ◽  
Keyword(s):  
Carbon Monoxide ◽  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Diesel Fuel ◽  
Hydrocarbon Fuel ◽  
Load Range ◽  
Engine Operation ◽  
Exhaust Gases ◽  
Wide Range ◽  
Diesel Cycle

The paper shows some ways to improve the environmental characteristics of a diesel engine using gaseous hydrocarbon fuel and operating the engine in a gas-diesel cycle mode. Some possibilities to reduce toxic components of exhaust gases in a gas-diesel engine operating on liquefi ed propane-butane mixtures have been studied. Experiments carried out in a wide range of load from 10 to 100% and speed from 1400 to 2000 rpm showed that the gas-diesel engine provides a suffi ciently high level of diesel fuel replacement with gas hydrocarbon fuel. The authors indicate some eff ective ways to reduce the toxicity of exhaust gases. The engine power should be adjusted by the simultaneous supply of fuel, gas and throttling the air charge in the intake manifold. This method enriches the fi rst combusting portions to reduce nitrogen oxides and maintains the depletion of the main charge within the fl ammability limits of the gas-air charge to reduce carbon monoxide and hydrocarbons. The authors found that when the engine operates in a gas-diesel cycle mode, the power change provides a decrease in nitrogen oxide emissions of gas-diesel fuel only due to gas supply in almost the entire load range as compared to the pure diesel. At high loads (more than 80%) stable engine operation is ensured up to 90% of diesel fuel replaced by gas. Even at 10% of diesel fuel used the concentration of nitrogen oxides decreases by at least 15…20% as compared with a diesel engine in the entire load range. However, there is an increased emission of hydrocarbons and carbon monoxide in the exhaust gases. Further experimental studies have shown that optimization of the gas diesel regulation can reduce the mass emission of nitrogen oxides contained in exhaust gases in 2…3 times and greatly reduce the emission of incomplete combustion products – carbon monoxide and hydrocarbons.

scholarly journals Bench Tests for Exhaust Gas Temperature Distribution in an Aircraft Piston Engine with and without a Turbocharger

2021 ◽  
Vol 15 (3) ◽  
pp. 155-166
Author(s):  
Jacek Czarnigowski ◽  
Krzysztof Skiba ◽  
Daniel Rękas ◽  
Karol Ścisłowski ◽  
Piotr Jakliński
Keyword(s):  
Temperature Distribution ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Piston Engine ◽  
Bench Tests ◽  
Exhaust Gas Temperature

scholarly journals Выбор системы газотурбинного наддува высокооборотного судового дизеля

2020 ◽  
Author(s):  
A.N. Berdnik ◽  
D.V. Timoshenko ◽  
A.V. Passar
Keyword(s):  
Exhaust System ◽  
Point Of View ◽  
Working Fluid ◽  
Effective Pressure ◽  
Working Capacity ◽  
Piston Engine ◽  
Modern Approach ◽  
Exhaust Gases ◽  
Exergy Method ◽  
Exhaust Systems

В статье представлены результаты исследования импульсной и изобарной систем выпуска поршневого двигателя в зависимости от среднего эффективного давления. Целью данной работы является выявление эффективного использования импульсной или изобарной системы выпуска с точки зрения потерь работоспособности газов при движении энергетического потока от цилиндров до турбины при форсировании поршневого двигателя по среднему эффективному давлению. Существующие системы газотурбинного наддува не имеют чёткой области использования в зависимости от среднего эффективного давления. До сих пор на практике в процессе создания более форсированных дизельных двигателей конструкторы вынуждены подбирать многие элементы выпускных систем на основе ранее приобретенного опыта эксплуатации предыдущих конструкций. Причина кроется в отсутствии понимания физической сущности процессов локальных потерь работоспособности рабочего тела, например, при движении газов от цилиндров двигателя к турбине. В работе получены новые результаты расчётов импульсной и изобарной систем выпуска двигателя Caterpillar 3508С в зависимости от уровня форсирования по среднему эффективному давлению с использованием метода характеристик, квазистационарного метода и эксергетического метода. Разработан комплексный подход к решению проблемы выбора оптимальной системы выпуска при форсировании по среднему эффективному давлению поршневого двигателя. Для решения поставленной цели исследования в работе применился современный подход к оценке эффективности различных систем газотурбинного наддува эксергетический метод. Полученные результаты подтверждают возможность использования эксергетического метода для оценки эффективности систем выпуска с точки зрения потерь работоспособности газов. Выбрана оптимальная система выпуска двигателя Caterpillar 3508С с точки зрения потерь работоспособности выпускных газов в зависимости от среднего эффективного давления.The article presents the results of the study of pulse and Isobaric exhaust systems of a piston engine depending on the average effective pressure. The purpose of this work is to identify the effective use of a pulsed or isobaric exhaust system from the point of view of the loss of working capacity of exhaust gases during the movement of the energy flow from cylinders to the turbine when forcing the piston engine according to the average effective pressure. Existing supercharging systems do not have a clear area of use depending on the average effective pressure. Until now, in practice, in the process of creating more forced diesel engines, designers are forced to select many elements of exhaust systems on the basis of previously acquired experience in the operation of previous designs. The reason lies in the lack of understanding of the physical essence of the processes of local losses of the working capacity working fluid, for example, during the movement of gases from the engine cylinders to the turbine. In the work are obtained new results of calculations of impulse and isobaric exhaust systems of Caterpillar 3508C engine depending on the level of forcing on the average effective pressure with the use of the characteristics method, the quasi-stationary method and the exergy method are obtained. A comprehensive approach to solving the problem of choosing the optimal exhaust system when forcing the piston engine according to the average effective pressure is developed. To solve the goal of the study, a modern approach to assessing the efficiency of various supercharging systems exergy method was applied. The obtained results confirm the possibility of using the exergy method to assess the efficiency of exhaust systems from the point of view of the losses of working capacity of exhaust gases. The selected optimum system of exhaust system of the Caterpillar 3508C engine in terms of the losses of working capacity of exhaust gases depending on the average effective pressure.

scholarly journals АНАЛІЗ КОНСТРУКЦІЇ ТА ТЕХНОЛОГІЇ ВИГОТОВЛЕННЯ ПЕРСПЕКТИВНИХ РОТОРНО-ПОРШНЕВИХ ДВИГУНІВ

2020 ◽  
pp. 28-37
Author(s):  
Борис Георгійович Тимошевський ◽  
Олександр Сергійович Митрофанов ◽  
Андрій Станіславович Познанський ◽  
Аркадій Юрійович Проскурін
Keyword(s):  
Cylinder Block ◽  
Design Stage ◽  
Piston Engine ◽  
Combustion Chambers ◽  
Engine Operation ◽  
Systematic Analysis ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Basic Parameters ◽  
Degree Of Filling

The article discusses the main directions of development of creating new modern and improving existing rotary piston engines. The need for a systematic analysis of existing similar engine designs is established to separate and systematize their advantages and disadvantages at the design stage. As an analysis of the design and manufacturing technology of the existing most promising rotary piston engines, turbocompressor-type circuits with a movable cylinder block is considered, the engines in which the combustion takes place outside the working cylinder, the drum-piston type with movable combustion chambers, rotary expanders, etc. It is established that the structure of the housing of rotary piston engines with an internal cylindrical surface, in which the rotor with working cylinders is located, allows the creation of economical and compact engines. This structure of the engines allows you to reduce vibration and make them safer to use. A comparison of the mechanisms of motion of existing rotary piston engines. Based on the analysis of existing schemes and the design of modern rotary piston engines, a sample of a new design 12 RPE-4.4/1.75 rotary piston engine is designed. The design and basic parameters of a new model of the 12 RPE-4.4/1.75 rotary piston engine with adjustable spool air distribution are presented. The engine has twelve evenly spaced cylinders, provides a balanced engine, and the ability to start at any position of the rotor. The design of the engine designed provides for a central control cam shaft, the rotation of which allows you to adjust the valve timing and engine operation due to the degree of filling of the cylinder in a fairly wide range. A feature of the design of the engine is also that the control cam allows you to change the direction of rotation of the central rotor. It was found that the design of the crank mechanism of the 12 RPE-4.4/1.75 engine is simple in structure and production technology, as well as more reliable compared to similar existing rotary piston engines.

Improvement of piston engine operation efficiency by direct conversion of the heat of exhaust gases into electric energy

2016 ◽  
Vol 54 (1) ◽  
pp. 105-112 ◽  
Author(s):  
A. I. Leontiev ◽  
R. Z. Kavtaradze ◽  
D. O. Onishchenko ◽  
A. S. Golosov ◽  
S. A. Pankratov
Keyword(s):  
Electric Energy ◽  
Direct Conversion ◽  
Piston Engine ◽  
Engine Operation ◽  
Exhaust Gases ◽  
Operation Efficiency

Measurement of cycle-resolved engine-out soot concentration from a diesel-pilot assisted natural gas direct-injection compression-ignition engine

2021 ◽  
pp. 146808742098626
Author(s):  
Pooyan Kheirkhah ◽  
Patrick Kirchen ◽  
Steven Rogak
Keyword(s):  
Response Time ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Exhaust System ◽  
Cycle Period ◽  
Scanning Mobility Particle Sizer ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Exhaust Port ◽  
Exhaust Stream

Exhaust-stream particulate matter (PM) emission from combustion sources such as internal combustion engines are typically characterized with modest temporal resolutions; however, in-cylinder investigations have demonstrated significant variability and the importance of individual cycles in transient PM emissions. Here, using a Fast Exhaust Nephelometer (FEN), a methodology is developed for measuring the cycle-specific PM concentration at the exhaust port of a single-cylinder research engine. The measured FEN light-scattering is converted to cycle-resolved soot mass concentration ([Formula: see text]), and used to characterize the variability of engine-out soot emission. To validate this method, exhaust-port FEN measurements are compared with diluted gravimetric PM mass and scanning mobility particle sizer (SMPS) measurements, resulting in close agreements with an overall root-mean-square deviation of better than 30%. It is noted that when PM is sampled downstream in the exhaust system, the particles are larger by 50–70 nm due to coagulation. The response time of the FEN was characterized using a “skip-firing” scheme, by enabling and disabling the fuel injection during otherwise steady-state operation. The average response time due to sample transfer and mixing times is 55 ms, well below the engine cycle period (100 ms) for the considered engine speeds, thus suitable for single-cycle measurements carried out in this work. Utilizing the fast-response capability of the FEN, it is observed that cycle-specific gross indicated mean effective pressure (GIMEP) and [Formula: see text] are negatively correlated ([Formula: see text]: 0.2–0.7), implying that cycles with lower GIMEP emit more soot. The physical causes of this association deserve further investigation, but are expected to be caused by local fuel-air mixing effects. The averaged exhaust-port [Formula: see text] is similar to the diluted gravimetric measurements, but the cycle-to-cycle variations can only be detected with the FEN. The methodology developed here will be used in future investigations to characterize PM emissions during transient engine operation, and to enable exhaust-stream PM measurements for optical engine experiments.

Effects of H2 Addition to CNG Blends on Cycle-to-Cycle and Cylinder-to-Cylinder Combustion Variation in an SI Engine

2012 ◽  
Author(s):  
Mirko Baratta ◽  
Stefano d’Ambrosio ◽  
Daniela Misul ◽  
Ezio Spessa
Keyword(s):  
Diagnostic Tool ◽  
Combustion Process ◽  
Experimental Tests ◽  
Test Point ◽  
Pollutant Emissions ◽  
Engine Operation ◽  
Pressure Transducers ◽  
Rate Analysis ◽  
Spark Plug ◽  
Wide Range

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter CNG (compressed natural gas) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure and temperature at different locations on the engine intake and exhaust systems as well as ‘engine-out’ pollutant emissions have been measured. The signals correlated to the engine operation have been acquired by means of a National Instruments PXI-DAQ system and a home developed software. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a CAD procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads and relative air-fuel ratios (up to the lean operation). For stoichiometric operation, the addition of hydrogen to CNG has produced a bsfc reduction ranging between 2 to 7% and a bsTHC decrease up to the 40%. These benefits have appeared to be even higher for lean mixtures. Moreover, hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. As a matter of fact, hydrogen addition has generally resulted into extended operation up to RAFR = 1.8. Still, a discrepancy in the abovementioned conclusions was observed depending on the engine cylinder considered.

Assessment of Certainty of Ventilation Processes Mathematical Modeling

2015 ◽  
Vol 725-726 ◽  
pp. 1255-1260
Author(s):  
Tamara Daciuk ◽  
Vera Ulyasheva
Keyword(s):  
Mathematical Modeling ◽  
Turbulent Flows ◽  
Turbulence Models ◽  
Field Measurements ◽  
Heat Emission ◽  
Emission Sources ◽  
Wide Range ◽  
Calculation Results ◽  
Definition Of ◽  
Semiempirical Models

Numerical experiment has been successfully used during recent 10-15 years to solve a wide range of thermal and hydrogasodynamic tasks. Application of mathematical modeling used to design the ventilation systems for production premises characterized by heat emission may be considered to be an effective method to obtain reasonable solutions. Results of calculation performed with numerical solution of ventilation tasks depend on turbulence model selection. Currently a large number of different turbulence models used to calculate turbulent flows are known. Testing and definition of applicability limits for semiempirical models of turbulence should be considered to be a preliminary stage of calculation. This article presents results of test calculations pertaining to thermal air process modeling in premises characterized by presence of heat emission sources performed with employment of different models of turbulence. Besides, analysis of calculation results and comparison with field measurements data are presented.

scholarly journals Optimization Aspects of an Ejector Type Hypersonic Thrust Nozzle

1992 ◽  
Author(s):  
G. Trittler ◽  
E. Eckert ◽  
M. Göing
Keyword(s):  
High Performance ◽  
Exhaust System ◽  
Vital Role ◽  
Calculation Model ◽  
Nozzle Geometry ◽  
Design Parameters ◽  
Axial Thrust ◽  
Thrust Coefficient ◽  
Wide Range ◽  
Low Performance

Hypersonic aircraft projects are highly dependant on efficient propulsion systems. High performance and integration within the airframe play a vital role in the overall concept. Particular attention must be paid to the exhaust system that is submitted to a wide range of operational requirements. An optimization of the nozzle geometry for high flight Mach numbers will lead to a low performance at the transonic flight regime. The additional use of secondary ejector air flow at transonic speeds is one option to improve the thrust behaviour of the nozzle. In the presented paper performance data of single expansion ramp ejector type nozzles are predicted using a calculation model based on a method-of-characteristics algorithm. For optimization purposes the effects of various design parameters on axial thrust coefficient and thrust vector angle are discussed. The geometric parameters investigated are the length of the lower nozzle wall and its deflection angle as well as the ejector slot location and its cross-section.

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