Method for Determining Instantaneous Temperature at the Surface of Combustion Chamber Deposits in an HCCI Engine

2012 ◽  
Author(s):  
Orgun Güralp ◽  
Paul Najt ◽  
Zoran S. Filipi
Keyword(s):  
Surface Temperature ◽  
Combustion Chamber ◽  
High Efficiency ◽  
Combustion Process ◽  
Heat Transfer Process ◽  
Valuable Insight ◽  
Hcci Combustion ◽  
Crank Angle ◽  
Instantaneous Temperature ◽  
Combustion Chamber Deposits

Homogeneous charge compression ignition (HCCI) combustion is widely regarded an attractive option for future high efficiency gasoline engines. HCCI combustion permits operation with a highly dilute, well mixed charge, resulting in high thermal efficiency and extremely low NOx and soot emissions, two qualities essential for future propulsion system solutions. Because HCCI is a thermo-kinetically dominated process, full understanding of how combustion chamber boundary thermal conditions affect the combustion process are crucial. This includes the dynamics of the effective chamber wall surface temperature, as dictated by the formation of combustion chamber deposits (CCD). It has been demonstrated that, due to the combination of CCD thermal properties and the sensitivity of HCCI to wall temperature, the phasing of auto-ignition can vary significantly as CCD coverage in the chamber increases. In order to better characterize and quantify the influence of CCDs, a numerical methodology has been developed which permits calculation of the crank-angle resolved local temperature profile at the surface of a layer of combustion chamber deposits. This unique predictor-corrector methodology relies on experimental measurement of instantaneous temperature underneath the layer, i.e. at the metal-CCD interface, and known deposit layer thickness. A numerical method for validation of these calculations has also been devised. The resultant crank-angle resolved CCD surface temperature and heat flux profiles both on top and under the CCD layer provide valuable insight into the near wall phenomena, and shed light on the interplay between the dynamics of the heat transfer process and HCCI burn rates.

Method for Determining Instantaneous Temperature at the Surface of Combustion Chamber Deposits in an HCCI Engine

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Orgun Güralp ◽  
Paul Najt ◽  
Zoran S. Filipi
Keyword(s):  
Surface Temperature ◽  
Combustion Chamber ◽  
High Efficiency ◽  
Combustion Process ◽  
Heat Transfer Process ◽  
Valuable Insight ◽  
Hcci Combustion ◽  
Crank Angle ◽  
Instantaneous Temperature ◽  
Combustion Chamber Deposits

Homogeneous charge compression ignition (HCCI) combustion is widely regarded as an attractive option for future high efficiency gasoline engines. HCCI combustion permits operation with a highly dilute, well mixed charge, resulting in high thermal efficiency and extremely low NOx and soot emissions, two qualities essential for future propulsion system solutions. Because HCCI is a thermokinetically dominated process, full understanding of how combustion chamber boundary thermal conditions affect the combustion process are crucial. This includes the dynamics of the effective chamber wall surface temperature, as dictated by the formation of combustion chamber deposits (CCD). It has been demonstrated that, due to the combination of CCD thermal properties and the sensitivity of HCCI to wall temperature, the phasing of autoignition can vary significantly as CCD coverage in the chamber increases. In order to better characterize and quantify the influence of CCDs, a numerical methodology has been developed which permits calculation of the crank-angle resolved local temperature profile at the surface of a layer of combustion chamber deposits. This unique predictor-corrector methodology relies on experimental measurement of instantaneous temperature underneath the layer, i.e., at the metal-CCD interface, and known deposit layer thickness. A numerical method for validation of these calculations has also been devised. The resultant crank-angle resolved CCD surface temperature and heat flux profiles both on top and under the CCD layer provide valuable insight into the near wall phenomena, and shed light on the interplay between the dynamics of the heat transfer process and HCCI burn rates.

The ultra-high efficiency gas turbine engine, UHEGT, Part II: A numerical study on reducing the stator blade surface temperature by indexing fuel injectors and using film cooling

2020 ◽  
pp. 095765092097353
Author(s):  
Seyed M Ghoreyshi ◽  
Meinhard T Schobeiri
Keyword(s):  
Surface Temperature ◽  
Gas Turbine ◽  
Film Cooling ◽  
Total Pressure ◽  
High Efficiency ◽  
Combustion Process ◽  
Blade Surface ◽  
Turbine Engine ◽  
Fuel Injectors ◽  
Stator Blade

In the Ultra-High Efficiency Gas Turbine Engine, UHEGT (introduced in our previous studies) the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed within the axial gaps before each stator row. This technology substantially increases the thermal efficiency of the engine cycle to above 45%, increases power output, and reduces turbine inlet temperature. Since the combustion process is brought into the turbine stages in UHEGT, the stator blades are exposed to high-temperature gases and can be overheated. To address this issue and reduce the temperature on the stator blade surface, two different approaches are investigated in this paper. The first is indexing (clocking) of the fuel injectors (cylindrical tubes extended from hub to shroud), in which the positions of the injectors are adjusted relative to each other and the stator blades. The second is film cooling, in which cooling holes are placed on the blade surface to bring down the temperature via coolant injection. Four configurations are designed and studied via computational fluid dynamics (CFD) to evaluate the effectiveness of the two approaches. Stator blade surface temperature (as the main objective function) along with other performance parameters such as temperature non-uniformity at rotor inlet, total pressure loss over the injectors, and total power production by rotor are evaluated for all configurations. The results show that indexing presents the most promising approach in reducing the stator blade surface temperature while producing the least amount of total pressure loss.

Design and Development of a New Landfill/Biogas Engine Oil for Modern, High BMEP Natural Gas Engines

2011 ◽  
Author(s):  
John D. Palazzotto ◽  
Joseph Timar ◽  
Alan T. Beckman
Keyword(s):  
Combustion Chamber ◽  
New Product Development ◽  
Power Output ◽  
Landfill Gas ◽  
Combustion Process ◽  
Development Project ◽  
Engine Oil ◽  
Combustion Dynamics ◽  
Brake Mean Effective Pressure ◽  
Combustion Chamber Deposits

The use of higher brake mean effective pressure (BMEP) engines in landfill or alternative gas applications has increased dramatically in the past few years. Operators are using these engines due to their ability to provide lower emissions coupled with improved economics for the end user due to the higher density or power output capability compared to an engine of similar size and displacement. Landfill gas (LFG) quality can vary greatly as well as the contaminant level due to the composition of the landfill. This environment poses unique challenges to both the engine and the engine oil, including shorter oil drain intervals, corrosive attack of engine components, with increased piston and combustion chamber deposits, to name but a few. Maintaining longer oil drain intervals minimizes unscheduled oil drains which can decrease the overall cost of the landfill operation. High BMEP engines provide higher power output but at the cost of increased maintenance in severe fuel applications. Excessive piston crown and combustion chamber deposits from landfill gas impurities can have a deleterious effect on engine emissions, which may lead to the inability to meet local emissions regulations. Engine lubricants must provide adequate oil life as well as minimizing deposit related issues that may negatively impact regular scheduled maintenance cycles, thus reducing engine downtime and increasing revenues. Traditionally, the approach has been that oils formulated for landfill applications used excess base reserve to sufficiently neutralize the acids being formed during the combustion process. Unfortunately, this approach increases the sulfated ash content of the lubricant which lends itself to increased ash deposits and negatively impacts the combustion dynamics of these high BMEP engines, which are sensitive to ash deposition. Based on requests for a longer life lubricant without compromising deposit control characteristics in serve landfill applications, a new product development project was specifically targeted for late model, high BMEP engines, which are prone to detonation and sensitive to ash related deposits. This paper presents the development bench testing, and proof of performance field evaluations of a new generation, low ash landfill gas engine oil.

A Numerical Study on Reducing the Stator Blade Surface Temperature in the Ultra-High Efficiency Gas Turbine Engine by Indexing Fuel Injectors and Using Film Cooling

2018 ◽  
Author(s):  
Seyed M. Ghoreyshi ◽  
Meinhard T. Schobeiri
Keyword(s):  
Surface Temperature ◽  
Gas Turbine ◽  
Film Cooling ◽  
Pressure Loss ◽  
Total Pressure ◽  
High Efficiency ◽  
Combustion Process ◽  
Blade Surface ◽  
Fuel Injectors ◽  
Stator Blade

The Ultra-High Efficiency Gas Turbine technology, UHEGT, has been introduced in our previous publications [1]-[4]. In UHEGT, the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed and integrated within the axial gaps before each stator row. As shown in the previous publications, this technology substantially increases the thermal efficiency of the engine to 45% and above. Since the combustion process is brought into the turbine stages in UHEGT, the stator blades are exposed to high temperature gases and are prone to be overheated. To address this issue, two different approaches are investigated in this paper in order to control and reduce the temperature on the stator blade surface. The first approach is indexing (clocking) of the fuel injectors (cylindrical tubes extended from hub to shroud), in which the positions of the injectors are adjusted relative to each other and the stator blades. The second approach is using film cooling, in which cooling holes are added on the blade surface to bring down the temperature via coolant injection. Four configurations are designed and studied via computational fluid dynamics (CFD) to evaluate the effectiveness of the two approaches. The objective functions in this evaluation are stator blade surface temperature, temperature non-uniformity at rotor inlet, total pressure loss over the injectors, and total power production by rotor. The results show that the second configuration, which uses the indexing approach, presents the most promising case in controlling the stator blade surface temperature. This configuration produces the lowest temperature distribution over the stator blade surface and the least amount of total pressure loss.

Design and Development of a New Landfill/Biogas Engine Oil for Modern, High BMEP Natural Gas Engines

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
John D. Palazzotto ◽  
Joseph Timar ◽  
Alan T. Beckman
Keyword(s):  
Combustion Chamber ◽  
New Product Development ◽  
Power Output ◽  
Landfill Gas ◽  
Combustion Process ◽  
Development Project ◽  
Engine Oil ◽  
Combustion Dynamics ◽  
Brake Mean Effective Pressure ◽  
Combustion Chamber Deposits

The use of higher brake mean effective pressure (BMEP) engines in landfill or alternative gas applications has dramatically increased in the past few years. Operators are using these engines due to their ability to provide lower emissions, coupled with improved economics for the end user due to the higher density or power output capability compared to an engine of similar size and displacement. Landfill gas (LFG) quality can vary greatly, along with the contaminant level due to the composition of the landfill. This environment poses unique challenges to both the engine and the engine oil, including shorter oil drain intervals, corrosive attack of engine components, with increased piston and combustion chamber deposits, to name but a few. Maintaining longer oil drain intervals minimizes unscheduled oil drains, which can decrease the overall cost of the landfill operation. High BMEP engines provide higher power output, however,at the cost of increased maintenance in severe fuel applications. Excessive piston crown and combustion chamber deposits from landfill gas impurities can have a deleterious effect on engine emissions, which may lead to the inability to meet local emissions regulations. Engine lubricants must provide adequate oil life along with minimizing deposit related issues that may negatively impact regular scheduled maintenance cycles, thus reducing engine downtime and increasing revenues. Traditionally, the approach has been that oils formulated for landfill applications used excess base reserve to sufficiently neutralize the acids being formed during the combustion process. Unfortunately, this approach increases the sulfated ash content of the lubricant, which lends itself to increased ash deposits and negatively impacts the combustion dynamics of these high BMEP engines, which are sensitive to ash deposition. Based upon requests for a longer life lubricant without compromising deposit control characteristics to serve landfill applications, a new product development project was specifically targeted for late model, high BMEP engines, which are prone to detonation and sensitive to ash related deposits. This paper presents the development bench testing, and proof of performance field evaluations of a new generation, low ash landfill gas engine oil.

scholarly journals On the Turbulence-Chemistry Interaction of an HCCI Combustion Engine

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5876
Author(s):  
Marco D’Amato ◽  
Annarita Viggiano ◽  
Vinicio Magi
Keyword(s):  
Combustion Chamber ◽  
Numerical Study ◽  
Combustion Process ◽  
Operating Conditions ◽  
Chemical Mechanism ◽  
Model Parameters ◽  
Time Duration ◽  
Hcci Engine ◽  
Hcci Combustion ◽  
Engine Combustion

A numerical study was carried out to evaluate the influence of engine combustion chamber geometry and operating conditions on the performance and emissions of a homogeneous charge compression ignition (HCCI) engine. Combustion in an HCCI engine is a very complex phenomenon that is influenced by several factors that need to be controlled, such as gas temperature, heat transfer, turbulence and auto-ignition of the gas mixture. An eddy dissipation concept (EDC) combustion model was used to take into account the interaction between turbulence and chemistry. The model assumed that reactions occur in small turbulent structures called fine-scales, whose characteristic lengths and times depend mainly on the turbulence level. The model parameters were slightly modified with respect to the standard model proposed by Magnussen, to correctly simulate the characteristics of the HCCI combustion process. A reduced iso-octane chemical mechanism with 186 species and 914 chemical reactions was employed together with a sub-mechanism for NOx. The model was validated by comparing the results with available experimental data in terms of pressure and instantaneous heat release rate. Two engine chamber geometries with and without a cavity in the piston were considered, respectively. The two engines provided significant differences in terms of fluid-dynamic patterns and turbulence intensity levels in the combustion chamber. The results show that combustion started earlier and proceeded faster for the flat piston, leading to an increase in both the peak pressure and gross indicated mean effective pressure, as well as a reduction of CO and UHC emissions. An additional analysis was performed by considering a case without swirl for the flat-piston case. Such an analysis shows that the swirl motion reduces the time duration of combustion and slightly increases the gross indicated work per cycle.

scholarly journals Numerical Modelling and Experimental Verification of the Low-Emission Biomass Combustion Process in a Domestic Boiler with Flue Gas Flow around the Combustion Chamber

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5837
Author(s):  
Przemysław Motyl ◽  
Danuta Król ◽  
Sławomir Poskrobko ◽  
Marek Juszczak
Keyword(s):  
Combustion Chamber ◽  
Gas Flow ◽  
High Efficiency ◽  
Combustion Process ◽  
Experimental Studies ◽  
Numerical Calculations ◽  
Biomass Combustion ◽  
The European Union ◽  
Wood Pellets ◽  
Low Emission

The paper presents the results of numerical and experimental studies aimed at developing a new design of a 10 kW low-emission heating boiler fired with wood pellets. The boiler is to meet stringent requirements in terms of efficiency (η > 90%) and emissions per 10% O2: CO < 500 mg/Nm3, NOx ≤ 200 mg/Nm3, and dust ≤ 20 mg/Nm3; these emission restrictions are as prescribed in the applicable ECODESIGN Directive in the European Union countries. An innovative aspect of the boiler structure (not yet present in domestic boilers) is the circular flow of exhaust gases around the centrally placed combustion chamber. The use of such a solution ensures high-efficiency, low-emission combustion and meeting the requirements of ECODESIGN. The results of the numerical calculations were verified and confirmed experimentally, obtaining average emission values of the limited gases CO = 91 mg/Nm3, and NOx = 197 mg/Nm3. The temperature measured in the furnace is 450–500 °C and in the flue it was 157–197 °C. The determined boiler efficiency was 92%. Numerical calculations were made with the use of an advanced CFD (Computational Fluid Dynamics) workshop in the form of the Ansys programming and a computing environment with the dominant participation of the Fluent module. It was shown that the results obtained in both experiments are sufficiently convergent.

Significant Contributions of the Diesel Research Laboratory

1950 ◽  
Vol 4 (1) ◽  
pp. 7-25 ◽  
Author(s):  
C. G. A. Rosen
Keyword(s):  
Combustion Chamber ◽  
Research Laboratory ◽  
Fuel Injection ◽  
Combustion Process ◽  
Check Valve ◽  
Injection Equipment ◽  
Fuel Pump ◽  
Engine Torque ◽  
Precombustion Chamber ◽  
Combustion Chamber Deposits

This review of Diesel engine development is based on the work carried out at the Diesel Research Laboratory of Caterpillar Tractor Co. under the sponsorship of the author as Director of Research. For many years intensive effort has been made to understand the combustion process in this type of engine by a better knowledge of the fundamentals of ignition and the mechanism of the combustion process, and this study has been developed in the laboratory on a competitive basis. Originally six combustion systems were put to trial and a modified precombustion-chamber engine won the palm of victory on the basis of its ability to maintain uniformity over extended periods of operation. Briefly, the character of the comparative combustion studies followed two general classifications: (1) visual combustion studies; (2) study of combustion-chamber deposits. In order to make extended studies of the combustion phenomena by visual means, a quartz window was designed to achieve maximum cleanliness without the distraction of soot condensation on the cold windows. The author describes the precombustion-chamber process, and deals with the composition of combustion gases, flame duration, temperature distribution, the mechanism of ignition, and combustion-chamber deposits. He also discusses the development of fuel-injection equipment, pretiming, precalibrating, and the evolution of the fuel pump; he describes the characteristics of several types of check valve and fuel valve, and the fuel-pump control of engine torque characteristics. Spray characteristics and the flow through the fuel-valve orifice are also examined. Comments are made upon materials for cylinder liners and piston rings, and the effect of fuel inclusions on cylinder wear; lubrication is also considered. It is believed that excellent performance has been achieved in the precombustion-chamber engine with a minimum of complication in the fuel-injection equipment, and that the development of this principle of combustion has not yet reached its limit of progress.

Sign in / Sign up

Export Citation Format

Share Document