A novel variable geometry turbine achieved by elastically restrained nozzle guide vanes

Author(s):  
Zhihui Wang ◽  
Chaochen Ma ◽  
Zhi Huang ◽  
Liyong Huang ◽  
Xiang Liu ◽  
...  

Variable geometry turbocharging is one of the most significant matching methods between turbocharger and engine, and has been proven to provide air boost for entire engine speed range as well as to reduce turbo-lag. An elastically constrained device designed for a novel variable geometry turbocharger was presented in this paper. The design of the device is based on the nozzle vane’s self-adaptation under interactions of the elastic force by elastically restrained guide vane and the aerodynamic force from flowing gas. The vane rotation mechanism of the novel variable geometry turbocharger is different from regular commercial variable geometry turbocharger systems, which is achieved by an active control system (e.g. actuator). To predict the aerodynamic performance of the novel variable geometry turbocharger, the flow field of the turbine was simulated using transient computational fluid dynamics software combined with a fluid–structure interaction method. The results show that the function of elastically constrained device has similar effectiveness as the traditional variable geometry turbocharger. In addition, the efficiency of the novel variable geometry turbocharger is improved at most operating conditions. Furthermore, a turbocharged diesel engine was created using the AVL BOOST software to evaluate the benefits of the new variable geometry turbocharger. The proposed novel variable geometry turbocharger can effectively improve the engine performance at mid-high speeds, such that the maximum decrease of brake-specific fuel consumption reaches 17.91% under 100% load and 3600 r/min engine condition. However, the engine power and brake-specific fuel consumption decrease significantly at low engine speed conditions, and the decrease is more than 26% under 1000 r/min.

Author(s):  
Teja Gonguntla ◽  
Robert Raine ◽  
Leigh Ramsey ◽  
Thomas Houlihan

The objective of this project was to develop both engine performance and emission profiles for two test fuels — a 6% water-in-diesel oil emulsion (DOE-6) fuel and a neat diesel (D100) fuel. The testing was performed on a single cylinder, direct-injection, water-cooled diesel engine coupled to an eddy current dynamometer. Output parameters of the engine were used to calculate Brake Specific Fuel Consumption (BSFC) and Engine Efficiency (η) for each test fuel. DOE-6 fuels generated a 24% reduction in NOX and a 42% reduction in Carbon Monoxide emissions over the tested operating conditions. DOE-6 fuels presented higher ignition delays — between 1°-4°, yielded 1%–12% lower peak cylinder pressures and produced up to 5.5% lower exhaust temperatures. Brake Specific Fuel consumption increased by 6.6% for the DOE-6 fuels as compared to the D100 fuels. This project is the first research done by a New Zealand academic institution on water-in-diesel emulsion fuels.


2015 ◽  
Vol 76 (5) ◽  
Author(s):  
N. R. Abdullah ◽  
Z. Michael ◽  
A. R. Asiah ◽  
A. J. Helmisyah ◽  
S. Buang

Biodiesel is used widely as an alternative fuel for diesel engine due to biodegradable, oxygenated, renewable and compatible with diesel engines . In fact, biodiesel emission has decreased the levels of potentially carcinogenic compounds. However, a certain biodiesel such as Jatropha Oil Methyl Ester (JOME) has resulted in the increase of specific fuel consumption and higher NOx emissions. Therefore, the objective of this study is to investigate the effects of Palm Oil Methyl Ester (POME) in the blended fuel (Fossil fuel + JOME) on the fuel consumption and exhaust emission. Experiments were carried out at a constant engine speed (2000 rpm) with variable of engine loads. Results show that the addition of POME leads to the significant reduction in brake specific fuel consumption (BSFC), Total hydrocarbons (THCs),  carbon monoxide (CO) and nitrogen dioxide (NOx) emissions. This study shows a huge difference for Total hydrocarbons emission of blends with 5% POME compared to blends with 10% and 15% of POME. Carbon monoxide emission for blends with 15% POME is the lowest at constant engine speed with various engine loads which in average is 53% lower than blends of 5% POME. This is because blends with higher percentage of POME has higher cetane number hence shortened the ignition delay resulted  in the lower possibility of formation of rich fuel zone and thus reduces CO emissions.  Moreover, the higher percentage of POME also resulted in lower NOx emission regardless of engine loads. The blends with 15% POME had the lowest NOx emission which is 25% less compared with the blends of 5% POME.  The study recommended that, additional POME to the blended fuel can be considered as a good initiative to improve blended fuel property for diesel engine due to its potential to improve engine emissions and reduce brake specific fuel consumption. In conclusion, the blends of POME into (Fossil fuel + JOME) improves engine emission without significantly increasing fuel consumption.


Author(s):  
Nikhil Dayanand ◽  
John D. Palazzotto ◽  
Alan T. Beckman

In order to investigate the possible environmental and economic benefits of lubricants optimized for stationary natural gas engine efficiency, a decision was made to develop a test stand to quantify the effects of lubricant viscosities and formulations on the brake specific fuel consumption. Many fuel economy tests already exist for evaluating gasoline and heavy duty diesel motor oils which have proven the benefit of fuel economy from different lubricant formulations. These engines would not be suitable tools for evaluating the fuel economy performance of lubricating oils formulated specifically for stationary natural gas engines, since there are significant differences in operating conditions, fuel type, and oil formulations. This paper describes the adaptation of a Waukesha VSG F11 GSID as a tool to evaluate fuel consumption performance. The performance of brake specific fuel consumption when using different formulations was measured at selected high loads and rated speed. The results of the testing program discuss the viscosity and additive effects of stationary natural gas engine oil formulations on brake specific fuel consumption. The results will detail the change in brake specific fuel consumption between natural gas engine oil formulations blended to varying viscosities and compared to a typical natural gas engine oil formulation with a viscosity of 13.8 cSt @ 100°C. The second portion of the test program explores the effect of different additive packages that were blended to the same finished oil viscosity. It was acknowledged that there were statistical differences in brake specific fuel consumption characteristics between lubricants different in viscosity and additive formulations.


Author(s):  
Zhihui Wang ◽  
Chaochen Ma ◽  
Hang Zhang ◽  
Fei Zhu

A turbocharger is a key enabler for energy conservation in an internal combustion engine. The turbine in a turbocharger is fed by highly pulsating gas flow due to the reciprocating engine, resulting in significant deterioration of the turbocharger performance. To solve this problem, a novel pulse-optimized regulation mechanism named ‘elastically restrained guide vane’ for a novel variable geometry turbocharger is proposed in this paper. The new mechanism regulates the instantaneous flow angle at turbine inlet due to guide vane's self-adaptive rotation under interactions of the elastic force by elastically restrained guide vane and the aerodynamic force from flowing gas, which is different from the traditional variable geometry turbocharger that is achieved by an active control system (e.g. actuator). To investigate the effectiveness of the novel method, a double-passage computational fluid dynamics model is built in ANSYS CFX software combined with a fluid-structure interaction method. The results demonstrate that the pulse-adaptive regulation method can effectively adjust the nozzle opening according to the different pulsating pressures at turbine inlet. Subsequently, based on the calibrated models, the numerical simulation concentrates on the potential gain in turbine eventual power output and the exhaust energy recover as well as the corresponding effects on efficiency as a result of operating the turbocharger in its elastically restrained guide vane mode compared to its operation as a conventional variable geometry turbocharger.


2013 ◽  
Vol 465-466 ◽  
pp. 221-225 ◽  
Author(s):  
Mohd Hafizil Mat Yasin ◽  
Rizalman Mamat ◽  
Abdul Mutalib Leman ◽  
Amir Khalid ◽  
Noreffendy Tamaldin

Biodiesel is an alternative, decomposable and biological-processed fuel that has similar characteristics with mineral diesel which can be used directly into diesel engines. However, biodiesel has its drawbacks which are more density and viscosity compared to mineral diesel. Alcohol additives implementation such as ethanol could reduce significantly the density and viscosity of the biodiesel. In this study, biodiesel (20%)-ethanol (5%)-diesel (75%), biodiesel (20%)-methanol (10%)-diesel (70%), biodiesel (20%)-ethanol (15%)-diesel (65%), biodiesel (20%)-ethanol (20%)-diesel (60%) and standard mineral diesel as a baseline fuel are tested in a Mitsubishi 4D68 diesel engine. Those test fuels are investigated under the same operating conditions at three different engine loads; 20%, 40% and 60% at a constant engine speed of 2500 rpm to determine the engine performance, combustion and emission of the diesel engine. Overall, biodiesel-ethanol-diesel blends show higher brake specific fuel consumption than mineral diesel especially at higher ethanol concentration. As ethanol proportions in blends increase, CO emissions increase, while NO emissions are reduced. Also, biodiesel-ethanol blend with 5% ethanol is more effective than other biodiesel-ethanol blends for reducing CO emissions and improve the combustion.


Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).


Author(s):  
A A Abdel-Rahman ◽  
M K Ibrahim ◽  
A A Said

This paper discusses the possibility of improving the part load performance of diesel electric turbocharged engines operating at constant speed conditions. A sequential turbocharged system is proposed, where the compressors are connected In series. The study focused on two turbocharged diesel–electric generating sets existing at Ameria Petroleum Refining Company in Alexandria, Egypt. The results of the prediction showed that, at part load, both the maximum pressure and temperature were increased, and the brake specific fuel consumption was reduced considerably (by about 10 per cent).


2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Murugan Kuppusamy ◽  
Thirumalai Ramanathan ◽  
Udhayakumar Krishnavel ◽  
Seenivasan Murugesan

The effect of thermal-barrier coatings (TBCs) reduces fuel consumption, effectively improving the engine efficiency. This research focused on a TBC with a thickness of 300 µm insulating the combustion chamber of a direct ignition (DI) engine. The piston crown, inlet and exhaust-valve head were coated using air-plasma-spray coating. Ceramic powder materials such as molybdenum (Mo) and aluminum oxide titanium dioxide (Al2O3-TiO2) were used. A performance test of the engine with the coated combustion chamber was carried out to investigate the brake power, brake thermal efficiency, volumetric efficiency, brake specific fuel consumption and air-fuel ratio. Also, an emission-characteristic test was carried out to investigate the emissions of unburned hydrocarbon (HC), carbon monoxide (CO), nitrogen oxides (NO, NO2, NO3) and smoke opacity (SO). The results reveal that the brake thermal efficiency and brake specific fuel consumption show significant increases because of these coating materials. The effect of the Al2O3-TiO2 coating significantly reduces the HC and CO engine emissions.


Author(s):  
Cleverson Bringhenti ◽  
Jesuino Takachi Tomita ◽  
Joa˜o Roberto Barbosa

This work presents the performance study of a 1 MW gas turbine including the effects of blade cooling and compressor variable geometry. The axial flow compressor, with Variable Inlet Guide Vane (VIGV), was designed for this application and its performance maps synthesized using own high technological contents computer programs. The performance study was performed using a specially developed computer program, which is able to numerically simulate gas turbine engines performance with high confidence, in all possible operating conditions. The effects of turbine blades cooling were calculated for different turbine inlet temperatures (TIT) and the influence of the amount of compressor-bled cooling air was studied, aiming at efficiency maximization, for a specified blade life and cooling technology. Details of compressor maps generation, cycle analysis and blade cooling are discussed.


2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Syed J. Khalid

Cruise specific fuel consumption (SFC) of turbofan engines is a key metric for increasing airline profitability and for reducing CO2 emissions. Although increasing design bypass ratio (BPR) of separate exhaust turbofan configurations improves cruise SFC, further improvements can be obtained with online control actuated variable geometry modulations of bypass nozzle throat area, core nozzle throat area, and compressor variable vanes (CVV/CVG). The scope of this paper is to show only the benefits possible, and the process used in determining those benefits, and not to suggest any particular control algorithm for searching the best combination of the control effectors. A parametric cycle study indicated that the effector modulations could increase the cruise BPR, core efficiency, transmission efficiency, propulsive efficiency, and ideal velocity ratio resulting in a cruise SFC improvement of as much as 2.6% depending upon the engine configuration. The changes in these metrics with control effector variations will be presented. Scheduling of CVV is already possible in legacy digital controls; perturbation to this schedule and modulation of nozzle areas should be explored in light of the low bandwidth requirements at steady-state cruise conditions.


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