High Efficiency Hybrid Cycle Engine

2006 ◽  
Author(s):  
Nikolay Shkolnik ◽  
Alexander C. Shkolnik
Keyword(s):  
Combustion Chamber ◽  
High Efficiency ◽  
Thermodynamic Cycle ◽  
Combustion Products ◽  
The Other ◽  
Energy Losses ◽  
Combustion Chambers ◽  
Extended Duration ◽  
Stroke Cycle ◽  
Hybrid Cycle

A “High Efficiency Hybrid Cycle” (HEHC) thermodynamic cycle is explored. This four-stroke cycle borrows elements from Otto, Diesel, Atkinson, and Rankine cycles. Air is compressed into an isolated combustion chamber, allowing for true isochoric combustion, and extended duration for combustion to proceed until completion. Combustion products expand into a chamber with greater volume than intake. We provide details of a compact HEHC design implementation using rotary pistons and isolated rotating combustion chambers. Two Pistons simultaneously rotate and reciprocate and are held in position by two roller bearings. One Piston performs intake and compression, while the other performs exhaust and expansion. We predict a reduction of energy losses, moving part counts, weight and size over conventional engines.

A Novel Gas Generator Concept for Jet Engines Using a Rotating Combustion Chamber

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Peter Jeschke ◽  
Andreas Penkner
Keyword(s):  
Combustion Chamber ◽  
High Efficiency ◽  
Weight Ratio ◽  
Thermodynamic Cycle ◽  
Ceramic Materials ◽  
Single Stage ◽  
Jet Engines ◽  
Gas Generator ◽  
Wetted Area ◽  
Flow Compressor

A gas generator—consisting of a single-stage shrouded mixed-flow compressor without a diffusor, a rotating combustion chamber, and a vaneless single-stage shrouded centripetal turbine—is presented and analyzed here. All components comprise a coherent rotating device, which avoids most of the problems usually associated with small gas generators. In other words, the concept avoids all radial clearances; it is vaneless, shortens the combustion chamber, minimizes the wetted area, and enables ceramic materials to be used, due to compressive blade stresses. However, the concept faces severe structural, thermal, and chemical reaction challenges and is associated with a large Rayleigh-type total pressure loss. All these features and their implications are discussed and their benefits and drawbacks for several jet engines are quantified, mainly by means of thermodynamic cycle calculations. As a result, it has been demonstrated that the concept offers a thrust-to-weight ratio which is higher than the standard when incorporated into small unmanned aerial vehicles (UAV)-type jet engines. It also enables an attractive multistage and dual-flow, but fully vaneless design option. However, the concept leads to a decrease in thermal efficiency if these were to be accomplished in the (small) core of turbofans with highest overall pressure ratios (OPRs) and high bypass ratios. In summary, the paper presents a gas generator approach, which may be considered by designers of small jet engines with high power density requirements, like those used in UAV applications. But this has been proven not to be an option for high-efficiency propulsion.

MULTIFOCAL IGNITION OF COMBUSTION CHAMBER BY SUBCRITICAL STREAMER MICROWAVE DISCHARGE

2020 ◽  
Author(s):  
P. V. Bulat ◽  
◽  
M. P. Bulat ◽  
P. V. Denissenko ◽  
V. V. Upyrev ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Microwave Discharge ◽  
Fuel Mixture ◽  
Combustion Products ◽  
Combustion Chambers ◽  
Entire Volume ◽  
Gas Pumping ◽  
Pumping Units

The challenges facing engine developers, aimed at improving the technical and operational characteristics, more stringent environmental standards, make the work aimed at increasing the efficiency of ignition, systems highly relevant. Technologies of prechamber, arc ignition, and ignition by corona discharge known to date require significant energy costs. In addition, ignition of a fuel mixture by such systems is local which leads to the limitation in the burning rate, incomplete combustion of fuel, and formation of harmful impurities in combustion products. Volumetric or multipoint ignition may significantly increase the effectiveness of the use of ignition systems. The use of a subcritical streamer microwave discharge, which is a network of thin hot channels propagating in the volume of the combustion chamber, seems promising because it provides virtually instantaneous ignition of the mixture in the entire volume. In this paper, the results of experiments using a subcritical streamer microwave discharge are presented. The possibility of volumetric ignition and a substantial increase in the completeness of fuel combustion is demonstrated. A number of indirect evidences indicate the absence of nitrogen oxides in combustion products. The results can be applied to the development of multivolumetric ignition systems in internal combustion engines, gas pumping units, power gas turbines, low-emission combustion chambers, etc.

Application of CFD-Based Analysis Technique for Design and Optimization of Gas Turbine Combustors

2004 ◽  
Author(s):  
I. G. Koutsenko ◽  
S. F. Onegin ◽  
A. M. Sipatov
Keyword(s):  
Nitric Oxide ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Combustion Products ◽  
Combustion Chambers ◽  
Design And Optimization ◽  
Gas Turbine Combustors ◽  
Analysis Technique ◽  
Nitric Oxide Emissions ◽  
Operational Development

The design and operational development of gas turbine combustors is a complex process, involving a great volume of design and experimental work. The application of computational fluid dynamics (CFD) methods allows to lower the volume of experimental works on operational development of combustors and to make changes to the design of combustion chambers on early design stages. In this paper the application of commercial CFD package CFX-TASCflow for calculation of flow structure and analysis of nitric oxide formation process in the combustion chamber of the PS-90A gas turbine and its modifications is considered. The results of the analysis show, that the basic determinative criterion of a nitric oxide emission level is the residence time of a combustion products in high-temperature zones. With help of this criterion, an optimization of the PS-90A combustion chamber was performed. A design of an optimized combustion chamber allows to achieve a low level of nitric oxide emissions.

ANALYSIS OF TECHNOLOGICAL POSSIBILITIES OF TWO-CHAMBER IMPULSE DEVICES FOR SHEET STAMPING

2022 ◽  
pp. 111-117
Author(s):  
А.Ю. Боташев ◽  
А.А. Мусаев
Keyword(s):  
Combustion Chamber ◽  
Fuel Mixture ◽  
Combustion Products ◽  
Small Scale ◽  
Scale Production ◽  
Technological Capabilities ◽  
Combustion Chambers ◽  
Ferrous Alloys ◽  
Stamping Process ◽  
Sheet Stamping

Проведен анализ технологических возможностей двухкамерных устройств для листовой штамповки с одной и двумя камерами сгорания. В устройствах с одной камерой сгорания штамповка детали происходит в холодном состоянии заготовки под действием на нее гибкой среды за счет кинетической энергии поршня, ускоряемого продуктами сгорания газообразной топливной смеси. В устройствах с двумя камерами сгорания процесс штамповки совершается с нагревом заготовки воздействием на нее горячего газа, образованного при сгорании в верхней камере предварительно сжатой топливной смеси. При этом сжатие смеси осуществляется за счет энергии продуктов сгорания, образованных в нижней камере сгорания. Доказано, что устройства с одной камерой сгорания целесообразно использовать для штамповки из пластичных сортов сталей деталей разнообразной формы толщиной до 4 мм и из пластичных цветных сплавов толщиной до 8 мм. Устройства с двумя камерами сгорания целесообразно использовать для штамповки деталей из малопластичных сортов алюминиевых, титановых сплавов и других труднодеформируемых сплавов. Двухкамерные устройства для листовой штамповки обладают широкими технологическими возможностями и могут быть эффективно использованы в мелкосерийных производствах для штамповки деталей различной формы We carried out the analysis of technological capabilities of two-chamber devices for sheet stamping with one and two combustion chambers. In devices with one combustion chamber, the stamping process is carried out in the cold state of the workpiece by the action of an elastic medium on it, using the kinetic energy of the piston accelerated by the combustion products of the gaseous fuel mixture. In devices with two combustion chambers, the stamping process is carried out with the heating of the workpiece by the action of the hot gas formed during combustion in the upper chamber of the pre-compressed fuel mixture. In this case, the mixture is compressed due to the energy of the combustion products formed in the lower chamber. We established that devices with one combustion chamber are expedient to be used for stamping parts of various shapes with a thickness of up to 4 mm and from plastic non-ferrous alloys with a thickness of up to 8 mm from ductile steels. Devices with two combustion chambers are advisable to be used for stamping parts from low-plastic grades of aluminum, titanium alloys and other hard-to-deform alloys. Two-chamber devices for sheet stamping have wide technological capabilities and can be effectively used in small-scale production for stamping parts of various shapes

scholarly journals Fast Accurate and Automatic Brushstroke Extraction

2021 ◽  
Vol 17 (2) ◽  
pp. 1-24
Author(s):  
Yunfei Fu ◽  
Hongchuan Yu ◽  
Chih-Kuo Yeh ◽  
Tong-Yee Lee ◽  
Jian J. Zhang
Keyword(s):  
Neural Network ◽  
Efficient Algorithm ◽  
Deep Neural Network ◽  
High Efficiency ◽  
State Of The Art ◽  
High Reliability ◽  
The Other ◽  
Manual Annotation ◽  
Stroke Extraction ◽  
Art Research

Brushstrokes are viewed as the artist’s “handwriting” in a painting. In many applications such as style learning and transfer, mimicking painting, and painting authentication, it is highly desired to quantitatively and accurately identify brushstroke characteristics from old masters’ pieces using computer programs. However, due to the nature of hundreds or thousands of intermingling brushstrokes in the painting, it still remains challenging. This article proposes an efficient algorithm for brush Stroke extraction based on a Deep neural network, i.e., DStroke. Compared to the state-of-the-art research, the main merit of the proposed DStroke is to automatically and rapidly extract brushstrokes from a painting without manual annotation, while accurately approximating the real brushstrokes with high reliability. Herein, recovering the faithful soft transitions between brushstrokes is often ignored by the other methods. In fact, the details of brushstrokes in a master piece of painting (e.g., shapes, colors, texture, overlaps) are highly desired by artists since they hold promise to enhance and extend the artists’ powers, just like microscopes extend biologists’ powers. To demonstrate the high efficiency of the proposed DStroke, we perform it on a set of real scans of paintings and a set of synthetic paintings, respectively. Experiments show that the proposed DStroke is noticeably faster and more accurate at identifying and extracting brushstrokes, outperforming the other methods.

scholarly journals Modeling of Spray Combustion with a Steady Laminar Flamelet Model in an Aeroengine Combustion Chamber Based on OpenFOAM

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Yinli Xiao ◽  
Zupeng Wang ◽  
Zhengxin Lai ◽  
Wenyan Song
Keyword(s):  
Combustion Chamber ◽  
High Performance ◽  
Numerical Models ◽  
Spray Combustion ◽  
Combustion Chambers ◽  
Flamelet Model ◽  
Steady Laminar ◽  
Good Agreement ◽  
Laminar Flamelet ◽  
Laminar Flamelet Model

The development of high-performance aeroengine combustion chambers strongly depends on the accuracy and reliability of efficient numerical models. In the present work, a reacting solver with a steady laminar flamelet model and spray model has been developed in OpenFOAM and the solver details are presented. The solver is firstly validated by Sandia/ETH-Zurich flames. Furthermore, it is used to simulate nonpremixed kerosene/air spray combustion in an aeroengine combustion chamber with the RANS method. A comparison with available experimental data shows good agreement and validates the capability of the new developed solver in OpenFOAM.

A General Rezoning Technique for KIVA3V Internal Combustion Engines CFD Simulations

2010 ◽  
Author(s):  
Randy P. Hessel ◽  
Ettore Musu ◽  
Salvador M. Aceves ◽  
Daniel L. Flowers
Keyword(s):  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Ad Hoc ◽  
National Laboratory ◽  
Internal Combustion ◽  
Computational Time ◽  
Combustion Engines ◽  
Combustion Chambers ◽  
Time Step ◽  
Engine Cycle

A computational mesh is required when performing CFD-combustion modeling of internal combustion engines. For combustion chambers with moving pistons and valves, like those in typical cars and trucks, the combustion chamber shape changes continually in response to piston and valve motion. The combustion chamber mesh must then also change at each time step to reflect that change in geometry. The method of changing the mesh from one computational time step to the next is called rezoning. This paper introduces a new method of mesh rezoning for the KIVA3V CFD-combustion program. The standard KIVA3V code from Los Alamos National Laboratory comes with standard rezoners that very nicely handle mesh motion for combustion chambers whose mesh does not include valves and for those with flat heads employing vertical valves. For pent-roof and wedge-roof designs KIVA3V offers three rezoners to choose from, the choice depending on how similar a combustion chamber is to the sample combustion chambers that come with KIVA3V. Often, the rezoners must be modified for meshes of new combustion chamber geometries to allow the mesh to successfully capture change in geometry during the full engine cycle without errors. There is no formal way to approach these modifications; typically this requires a long trial and error process to get a mesh to work for a full engine cycle. The benefit of the new rezoner is that it replaces the three existing rezoners for canted valve configurations with a single rezoner and has much greater stability, so the need for ad hoc modifications of the rezoner is greatly reduced. This paper explains how the new rezoner works and gives examples of its use.

scholarly journals METHOD OF CONTROLLING PRESENCE OF FOREIGN SUBSTANCES AND OBJECTS IN THE BORE OF THE BARREL USING MONOCHROME LIGHT

2021 ◽  
pp. 53-57
Author(s):  
V. Kozachuk ◽  
M. Sliusarenko
Keyword(s):  
Combustion Products ◽  
The Other ◽  
Light Sources ◽  
Current Value ◽  
Precision And Accuracy ◽  
Shell Particles ◽  
The Military ◽  
Parameter Values ◽  
The Impact ◽  
Powder Combustion

In the article, the authors propose a method for controlling the presence of foreign substances and objects inside the barrel. The problem of surface cleanliness control remains relevant in many areas, ranging from sanitary cleaning to nanoelectronics. In the military sphere, this becomes particularly important during the cleaning of cannon barrels. Both powder combustion products and cartridge cap and bullet shell particles are deposited in the barrel during firing from guns. Under the impact of high temperatures, the bullet particles are partially oxidized and cover the barrel channel with a thin layer of deposit of oxides, which are difficult to dissolve. As a result, the density of the bullet abuting the walls changes. This affects the characteristics of its motion inside the barrel. The accuracy of the shot is reduced, and subsequently the precision and accuracy of shooting in general decreases. The essence of the proposed method consists in the fact that a light source is placed in the bore of the barrel on one side, and an optical device is placed on the other side, with the help of which the presence of foreign substances and objects is monitored. Unlike the known methods, this method is characterized in that several monochrome light sources in addition are placed in turn in the bore of the barrel from the breech part, and in the bore of the barrel from the muzzle part there is equipment for receiving (detecting) monochrome light. Then, obtained monochrome light is analyzed, current value of its defined parameters is determined. At the next stage, parameter values of monochrome light fixed during control are compared with parameter values of reference signatures, which had been obtained before the barrel was put in service. These values are stored in equipment memory. If the values of at least one of the parameters from at least one of the monochrome light sources are found to be inconsistent with the parameters of the reference signatures, the equipment for receiving and analyzing monochrome light gives a signal about the presence of foreign substances and objects in the bore of the barrel.

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