Begell House Inc.
Atomization and Sprays
AAS
1044-5110
21
6
2011
QUANTITATIVE ANALYSES OF FUEL SPRAY-AMBIENT GAS INTERACTION BY MEANS OF LIF-PIV TECHNIQUE
447-465
10.1615/AtomizSpr.2011003894
Jingyu
Zhu
Mazda Motor Corporation, 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima 730-8670, Japan
Keiya
Nishida
Department of Mechanical System Engineering, University of Hiroshima, 1-4-1
Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
Olawole Abiola
Kuti
Department of Mechanical System Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739-8527, Japan
Seoksu
Moon
Department of Mechanical Engineering, Inha University, Incheon, South Korea
diesel spray
ultrahigh injection pressure
micro-hole nozzle
ambient gas flow
mass flow rate
LIF-PIV
The in-cylinder fuel-ambient gas mixing property in a direct injection (D.I.) diesel engine significantly influences the ensuing combustion and exhaust emission performance. In this study, the interaction of nonevaporating diesel spray with the surrounding gas was analyzed quantitatively in the quiescent condition at room temperature and with ambient gas pressure of 1 MPa by means of the laser induced fluorescence-particle image velocimetry (LIF-PIV) technique. Particularly, this study focused on the calculation of gas mass flow rate entrained through the entire spray region (spray side periphery and tip region) and total entrained gas-fuel ratio by using the gas velocity data obtained by the LIF-PIV technique. Another focus of this study was the gas entrainment characteristics of diesel spray under a wide range of injection pressures (100, 200, and 300 MPa) and the micro-hole nozzle (0.08mm) condition. The results indicate that the entrained gas mass flow rate at the spray tip region is prominent in the whole periphery and the proportion of gas entrainment at the side surface region increases as the spray develops Higher injection pressure significantly enhances the total entrained gas mass; however the increase of ambient gas/fuel mass ratio becomes moderate gradually as the injection pressure increases. The calculation model proposed by this work is capable of illustrating the ambient gas flow characteristics of the diesel spray accurately.
EXPERIMENTAL STUDIES ON HIGH-PRESSURE SPRAY STRUCTURE OF BIOFUELS
467-481
10.1615/AtomizSpr.2011004023
Devendra
Deshmukh
Indian Institute of Science Bangalore, India
R. V.
Ravikrishna
Combustion & Spray Laboratory, Department of Mechanical Engineering, Indian Institute of Science, Bangalore, 560012, India
biofuel
vegetable oil
SMD
tip penetration
The high-pressure spray characteristics of biofuels, specifically, Pongamia oil and its blends with diesel are studied for various gas pressures. Two single-hole solenoid injectors with nozzle diameters of 200 and 260 µm are used along with a high-pressure common-rail direct-injection system to inject fuel into a high-pressure spray visualization chamber. The spray structure is characterized using a high-speed laser-based shadowgraphy technique. The spray structure of Pongamia oil revealed the presence of an intact liquid core at low gas pressure. At high gas pressures, the spray atomization of the Pongamia oil showed marked improvement. The spray tip penetration of Pongamia oil and its blends with diesel is higher compared to that of diesel for all test conditions. The spray cone angle of Pongamia oil and 50% Pongamia oil blend with diesel is lower as compared to that of diesel. Both these observations are attributed to the presence of large droplets carrying higher momentum in oil and blend. The droplet size is measured at an injection pressure of 1000 bar and gas pressure of 30 bar at 25 mm below the nozzle tip using the particle/droplet image analysis (PDIA) method. The droplet size measurements have shown that the Sauter mean diameter (SMD) in the spray core of Pongamia oil is more than twice that of diesel. The spray tip penetration of the 20% blend of Pongamia with diesel (P20) is similar to that of diesel but the SMD is 50% higher. Based on experimental data, appropriate spray tip penetration correlation is proposed for the vegetable oil fuels such as Pongamia.
PREDICTION OF SIZE AND VELOCITY DISTRIBUTIONS IN SPRAYS FORMED BY THE BREAKUP OF PLANAR LIQUID SHEETS USING MAXIMUM ENTROPY FORMALISM
483-501
10.1615/AtomizSpr.2011003709
Sujit
Nath
Department of Mechanical Engineering,
National Institute of Technology Silchar,
Cachar, Assam, India, 788010
Amitava
Datta
Power Engineering Department, Jadavpur University, Salt Lake Campus, Kolkata 700098, India
Achintya
Mukhopadhyay
Department of Mechanical Engineering, Jadavpur University, Kolkata-700032,
West Bengal, India
Swarnendu
Sen
Department of Mechanical Engineering, Jadavpur University, Kolkata 700032, India
T. John
Tharakan
Liquid Propulsions Systems Centre, Indian Space Research Organization,Valiamala, Thiruvananthapuram 695547, India
maximum entropy principle
droop size distribution
drop velocity distribution
SMD
A predictive model for size and velocity distributions of droplets in a liquid spray from the disintegration of a planar sheet has been proposed, based on the maximum entropy formulation (MEF) principle. The conservation laws of mass, momentum, and energy over the breakup region serve as the constraint conditions in the MEF model. The liquid sheet breakup length, evaluated from the nonlinear stability analysis of planar liquid sheet, is used to evaluate the momentum and energy exchange terms in the conservation equations. The mass mean diameter is calculated from the breakup of cylindrical ligaments using the deformed interface profile at the time of breakup. The simulated results of the droplet size distribution are compared with the results published in the literature and reasonable agreement is observed at different conditions. The investigation has brought out the effects of gas-to-liquid velocity ratio, gas-to-liquid density ratio, and Weber number on the droplet size and velocity distributions in the liquid spray.
ANALYSIS OF TRANSIENT LIQUID AND VAPOR PHASE PENETRATION FOR DIESEL SPRAYS UNDER VARIABLE INJECTION CONDITIONS
503-520
10.1615/AtomizSpr.2011003721
Jose V.
Pastor
CMT Motores Termicos−Universitat Politecnica de Valencia, Camino Vera s/n−46022 Valencia, Spain
Raul
Payri
CMT-Motores Térmicos, Universitat Politècnica de València, València, Spain
JOSE M
GARCIA-OLIVER
Universitat Politècnica de València
Francisco J.
Briceno
CMT-Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain
diesel sprays
multihole nozzle
multiple injections
liquid length
vapor penetration
The objective of this study is to investigate liquid length and vapor penetration for diesel sprays under highly transient injection conditions. High-speed Mie-scattering and shadowgraphy imaging of the spray evolution in an ambient of nitrogen are performed in a slow rotational optically accessible engine. Liquid length and vapor penetration were obtained for both single- and multiple-pulse (pilot-main and pilot-main-post) cases in a seven-hole nozzle that performs real engine injection strategies. In-cylinder temperature and density were simulated to reproduce operating conditions of a real engine at low load. Results show that liquid and vapor penetration coincide at the beginning of each injection pulse. For long injection pulses, liquid length can stabilize after some time, while penetration keeps growing. However, for short pulses liquid length has a highly transient evolution. Measurements were compared to calculations from a one-dimensional spray model that can predict spray evolution under highly transient conditions. No significant differences compared to experimental data were found in terms of penetration. Regarding liquid length, major differences were found in the opening and closing transients. Multiple injection analysis of the interaction between pulses was performed by means of the model results; previously single-pulse cases were used to calibrate the model.
MEASUREMENT OF INITIAL CONDITIONS OF A KEROSENE SPRAY FROM A GENERIC AEROENGINE INJECTOR AT ELEVATED PRESSURE
521-535
10.1615/AtomizSpr.2011003457
Stefan
Freitag
German Aerospace Center−DLR, Institute of Propulsion Technology, Linder Hohe, 51147 Cologne, Germany
U.
Meier
German Aerospace Center−DLR, Institute of Propulsion Technology, Linder Hohe, 51147 Cologne, Germany
Johannes
Heinze
German Aerospace Center−DLR, Institute of Propulsion Technology, Linder Hohe, 51147 Cologne, Germany
Thomas
Behrendt
Institute of Propulsion Technology, German Aerospace Center, Linder Hohe, 51147 Koln, Germany
Christoph
Hassa
German Aerospace Center−DLR, Institute of Propulsion Technology, Linder Hohe, 51147 Cologne, Germany
aeroengine
airblast injector
elevated air pressure
phase Doppler anemometry
fuel flux measurements
Ab initio prediction of aeroengine sprays at realistic conditions is currently not feasible and will remain so for a significant time to come. As a partial solution to the problem, experimental data are generated to validate advanced combustion codes. For that purpose a generic injector was built and operated in an optical single sector combustor. Phase Doppler anemometry and Mie scattering were used. The in-house algorithm for the calculation of volume flux was modified to suit the experimental setup. Measurements were performed at 4 and 10 bars. Good volume flux density results can be obtained within the lift-off distance of the flame.