EXPERIMENTAL VALIDATION AND COMBUSTION CHAMBER GEOMETRY OPTIMIZATION OF DIESEL ENGINE BY USING DIESEL RK

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1 INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) International Journal of Mechanical Engineering and Technology (IJMET), ISSN (Print), ISSN (Print) ISSN (Online) Volume 6, Issue 2, February (2015), pp IAEME: Journal Impact Factor (2015): (Calculated by GISI) IJMET I A E M E EXPERIMENTAL VALIDATION AND COMBUSTION CHAMBER GEOMETRY OPTIMIZATION OF DIESEL ENGINE BY USING DIESEL RK SK. Abdul Siddique 1, K. Vijaya Kumar Reddy 2 1 Research Scholar, Jawaharlal Nehru Technological University Hyderabad 2 Professor, Jawaharlal Nehru Technological University Hyderabad ABSTRACT Compression ignition diesel engines are very popular both in stationary and mobile applications. These engines find large applications because of their higher compression ratios, robustness in design and higher thermal efficiencies. Air is sucked in to the chamber when the piston moves from TDC to BDC through the intake manifold during suction stroke. The fuel in atomized form is sprayed onto the compressed air in the chamber. The proper mixing of air and fuel in shorter time is essential to lessen the ignition lag phase. In order to get proper air fuel mixing, a systematic air movement also called swirl is essential, which produce higher relative velocity between fuel droplets and air. The spray cone of the injected liquid fuel gets disturbed because of air movement and turbulence inside the chamber. Since, the turbulence is mandatory for proper mixing and the fact that this could be achieved by the shape of the combustion chamber geometry, makes this research work is necessary. The present research work concentrates on combustion chamber geometry of single cylinder four stroke DI diesel engine with specification of 5.2kw, 1500rpm. Key Words: Diesel Engine, Simulation, Air-Fuel Ratio, Turbulence. INTRODUCTION Internal combustion engine is a reliable power source in the transportation, industrial and agriculture fields. From the literature, it is noted that several research studies are conducted to increase the performance of the diesel engine by modifying injection pressure, injection timing, exhaust gas recirculation etc,. The proper mixing of air and fuel in shorter time is essential to lessen 92

2 the ignition lag phase. In order to get proper air fuel mixing, a systematic air movement also called swirl is essential, which produce higher relative velocity between fuel droplets and air. The spray cone of the injected liquid fuel gets disturbed because of air movement and turbulence inside the chamber. The present research work concentrates on combustion chamber geometry of single cylinder four stroke DI diesel engine with specification of 5.2kw, 1500rpm. This system is having a hemi spherical shaped combustion chamber with single injector having three 0.3mm nozzles. In this research paper, four combustion chamber geometries (1) Toroidal, (2) Shallow Depth, (3) Re-entrant and (4) Double wedge shallow are considered for optimisation. Computational Fluid Dynamics software Diesel-RK is used to model the combustion phenomenon in compression ignition diesel engine. Hemispherical combustion chamber is the baseline geometry considered for validation of CFD tool Diesel-RK. MODELLING AND SIMULATION Diesel-RK is a modeling and simulation software specifically developed for thermodynamic engine simulation. DIESEL-RK software is developed in in the department of Internal Combustion Engines (Piston Engines), Bauman Moscow State Technical University. It is mainly designed for simulating and optimizing the working processes of internal combustion engines with all types of boosting. This software is used for torque curves, engine performance predictions, fuel consumption predictions, emission analysis and optimization of fuel injection profile including multiple injection, sprayer design and location as well as piston bowl shape optimization in models of DI Diesel engines. In the present simulation study, Diesel-RK software is used for calculation of performance and emission values for hemispherical piston bowl in which Diesel is used as fuel. In figure 1 shows hemispherical piston bowl modelled with Diesel- RK. EXPERIMENTATIONS Fig. (1): Modeling of hemispherical combustion chamber Experimentation is done on a single cylinder, four stroke, vertical, water cooled, direct injection computerized Kirloskar make CI Engine. The specifications of the engine are mentioned in the table 1. Fig 2 shows the experimental setup of the engine. The engine is attached with a DC electrical dynamometer to measure its output. Smoke measurement is done by using photo electronic smoke detection. Other emissions like Carbon dioxide, Nitrogen oxide and unused oxygen are found in 5 gas emission analyser. The experiments are conducted at different loads at constant rated speed of 1500rpm. 93

3 Fig (2): Experimental setup Table 1. Engine specifications No. of cylinders 01 No. of Strokes 04 Fuel Diesel Power rating 5.2 KW/ RPM Bore & Stroke 87.5 & 110 mm C R 17.5:1 Dynamometer arm length 185 mm Validation of CFD tool Diesel RK The comparison of the results obtained from the experimental investigations and from simulations by DIESEL-RK software are presented in figure (3). All the results are analysed by varying the load at rated constant speed of 1500rpm. The simulations are carried out on hemispherical combustion chamber geometry. The simulation results such as specific fuel consumption, mechanical efficiency, and exhaust emission CO 2, NOx are showed good agreement with experimental results. Variation of SFC w.r.t BP Variation of Mech. Efficiency w.r.t BP 94

4 Variation of CO 2 w.r.t BP Variation of NOx w.r.t BP Fig. (3) Hemispherical chamber simulation results Optimization study of combustion chamber geometry Fig. (4) Modeling of combustion chamber geometries 95

5 Table (1): Input Parameters considered for simulation Engine Specifications Connecting rod length 234mm No. of fuel injectors 01 No. of nozzles 03 Injector nozzle bore Inlet valves opening Inlet valve closing Start of fuel injection Exhaust valve opening Exhaust valve closing In diesel engines, fuel is injected into the combustion chamber and mixed with the compressed air. Proper mixing of fuel and air is important to produce controlled burn rate. Combustion chamber geometry is the key element in air fuel mixing process. In the present research paper, an attempt is made to simulate the critical combustion and put efforts to optimize the combustion chamber geometry. In this research paper, four combustion chamber geometries (1) Toroidal, (2) Shallow Depth, (3) Re-entrant and (4) Double wedge shallow are considered for investigation. Fig (4) shows the four combustion chamber models developed in Diesel RK for simulation. The input parameters considered for simulation are mentioned in table (1). RESULTS Single cylinder, 4 stroke Diesel, water cooled, power 5.2 kw at 1500 rpm, stroke 110 mm, bore 87.5 mm. 661 cc, CR mm before TDC after BDC 23 0 before TDC before BDC after TDC In this investigation, four pistons of different configurations suitable to 5.2kw single cylinder four stroke DI diesel engine are considered. The hemispherical shaped geometry is taken as a base engine combustion chamber geometry. In the present work, simulations are conducted to investigate the performance, emission and combustion characteristics using diesel fuel alone at different loads by using DIESEL -RK. The following graphs shows the results of different efficiencies, exhaust emissions, specific fuel consumptions and cylinder pressures for all combustion chamber geometries. 96

6 CONCLUSION Fig (3) Simulation results The 5.2kW, Kirlosker make single cylinder, four stroke engine is selected for investigation because it can withstand higher pressures and also is used extensively in agriculture and industrial sectors. The DIESEL-RK is used to simulate the combustion characteristics of direct injection diesel engine. The CFD tool is validated with experimental results. A good agreement between the modelling and experimental data ensures the accuracy of the numerical predictions. Four combustion chamber geometries, toroidal, shallow depth, re-entrant and double wedge shallow shapes are selected for simulation. Simulated results including specific fuel consumption, rate of pressure rise, heat release rate, mechanical efficiency, volumetric efficiency and exhaust emission have been analysed. The comparison revels that re-entrant combustion chamber geometry is the best among the selected geometry configurations. It exhibits lower emissions, lower specific fuel consumption rate, improved performance compared to other shapes. From the results, it is concluded that the numerical simulation is one of the powerful tool for optimisation and to improve performance of internal combustion engine instead of developing a new proto type systems and test and evaluate every time. 97

7 REFERENCES 1. P. Vijayakumaran, et al, Numerical simulation of combustion chamber geometry on a H.S.D.I. diesel engine a CFD approach, IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE, PP A.M. Indrodia1, et al, Investigation of different combustion chamber Geometry of diesel engine using CFD modelling of in cylinder Flow for improving the performance of Engine, 5th International & 26th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12th 14th, 2014, IIT 3. Hariram.V, Experimental investigation and optimization study of combustion chamber geometry on performance and emission parameters using Rice bran biodiesel, International Journal of Engineering Research and Development, Volume 10, Issue 11 (November 2014), PP Ranganatha Swamy L, et al, Effect of Injection Timing, Combustion Chamber Shapes and Nozzle Geometry on the Diesel Engine Performance Universal Journal of Petroleum sciences 2 (2014), S. Jafarmadar, A Computational Study of the Effects of Combustion Chamber Geometries on Combustion Process and Emission in a DI Diesel Engine, Journal of Fuel and Combustion Vol. 1, No. 1, Sept Mamdoh Al-Busoul, Aiman Al-Alawin, and Hamza Al-Tahaineh, Influence of Air-Fuel Ratio and Particle Size on Fluidized Bed Combustion of The El-Lajjun Oil Shale International Journal of Mechanical Engineering & Technology (IJMET), Volume 4, Issue 5, 2013, pp , ISSN Print: , ISSN Online: R. Senthil Kumar and M. Prabu, Experimental Investigation of A Di Diesel Engine Using Tyre Pyrolysis Oil-Diesel Blends as A Biodiesel International Journal of Mechanical Engineering & Technology (IJMET), Volume 5, Issue 2, 2014, pp , ISSN Print: , ISSN Online: S.Sunil Kumar Reddy and Dr. V. Pandurangadu, Theoritical Investigations of Injection Pressure In A Four Stroke Di Diesel Engine with Alcohol as Fuel International Journal of Mechanical Engineering & Technology (IJMET), Volume 4, Issue 2, 2013, pp , ISSN Print: , ISSN Online: