Effect of Viscosity and Heating Temperature on an Intermittent Spray Jet of Starch Dispersion

2014 ◽  
Vol 695 ◽  
pp. 459-462
Author(s):  
Muhammad Yasin Naz ◽  
Shaharin Anwar Sulaiman ◽  
Bambang Ari-Wahjoedi
Keyword(s):  
High Speed ◽  
Heating Temperature ◽  
Cone Angle ◽  
Imaging Study ◽  
Injection Time ◽  
Jet Injection ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Load Pressure ◽  
Jet Breakup

In this paper, an attempt was made to integrate the effect of jet injection time, load pressure and solution physical properties on jet breakup parameters. A starch-urea-borax complex solution was prepared and tested with an axi-symmetric full cone nozzle. The jet injection time was set to 100, 200, 300 and 400, the solution heating temperature was set to 20°C and 80°C ms, the load pressure was set to 1, 2, 3, 4, and 5 bar, and corresponding spray patterns were imaged by using a high speed camera. The imaging study of the developing spray patterns revealed that the unheated solution forms only spinning jets for all used load pressures. No jet breakup was seen in the near and far-nozzle imaged regions except at 5 bar load pressure, where minor spreading in the jet was seen after 80 mm downstream of the nozzle exit. At 80°C temperature and 5 bar load pressure, very dense spray patterns with an increased spray cone angle were emerging from the nozzle. After 300 ms of injection time, these developing spray jets were changed into fine spray patterns.

scholarly journals Characterization of Modified Tapioca Starch Solutions and Their Sprays for High Temperature Coating Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
M. Y. Naz ◽  
S. A. Sulaiman ◽  
B. Ariwahjoedi ◽  
Ku Zilati Ku Shaari
Keyword(s):  
High Speed ◽  
Heating Temperature ◽  
Complex Viscosity ◽  
Effect Of Temperature ◽  
Mean Flow ◽  
Spray Cone ◽  
Load Pressure ◽  
Tapioca Starch ◽  
Jet Breakup

The objective of the research was to understand and improve the unusual physical and atomization properties of the complexes/adhesives derived from the tapioca starch by addition of borate and urea. The characterization of physical properties of the synthesized adhesives was carried out by determining the effect of temperature, shear rate, and mass concentration of thickener/stabilizer on the complex viscosity, density, and surface tension. In later stage, phenomenological analyses of spray jet breakup of heated complexes were performed in still air. Using a high speed digital camera, the jet breakup dynamics were visualized as a function of the system input parameters. The further analysis of the grabbed images confirmed the strong influence of the input processing parameters on full cone spray patternation. It was also predicted that the heated starch adhesive solutions generate a dispersed spray pattern by utilizing the partial evaporation of the spraying medium. Below 40°C of heating temperature, the radial spray cone width and angle did not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The discharge coefficient, mean flow rate, and mean flow velocity were significantly influenced by the load pressure but less affected by the temperature.

scholarly journals Investigation of Vortex Clouds and Droplet Sizes in Heated Water Spray Patterns Generated by Axisymmetric Full Cone Nozzles

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
M. Y. Naz ◽  
S. A. Sulaiman ◽  
B. Ariwahjoedi ◽  
Ku Zilati Ku Shaari
Keyword(s):  
Nozzle Exit ◽  
High Speed ◽  
Heating Temperature ◽  
Cone Angle ◽  
Hot Water ◽  
Orifice Diameter ◽  
Detailed Knowledge ◽  
Water Spray ◽  
Spray Cone ◽  
Load Pressure

The hot water sprays are an important part of many industrial processes, where the detailed knowledge of physical phenomena involved in jet transportation, interaction, secondary breakup, evaporation, and coalescence of droplets is important to reach more efficient processes. The objective of the work was to study the water spray jet breakup dynamics, vortex cloud formation, and droplet size distribution under varying temperature and load pressure. Using a high speed camera, the spray patterns generated by axisymmetric full cone nozzles were visualized as a function water temperature and load pressure. The image analysis confirmed that the spray cone angle and width do not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The formation and decay of semitorus like vortex clouds were also noticed in spray structures generated at near water boiling point temperature. For the nozzle with smallest orifice diameter (1.19 mm), these vortex clouds were very clear at 90°C heating temperature and 1 bar water load pressure. In addition, the sauter mean diameter (SMD) of the spray droplets was also measured by using Phase Doppler Anemometry (PDA) at different locations downstream of the nozzle exit. It was noticed that SMD varies slightly w.r.t. position when measured at room temperature whereas at higher temperature values, it became almost constant at distance of 55 mm downstream of the nozzle exit.

Experimental Study on Spray Characteristics of Diesel Engines and Analysis of Fuel Dripping Phenomenon

2014 ◽  
Vol 1078 ◽  
pp. 271-275 ◽  
Author(s):  
Yu Qiang Wu ◽  
Qian Wang ◽  
Zhi Sheng Gao ◽  
Zhou Rong Zhang ◽  
Li Ming Dai
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Cone Angle ◽  
Digital Camera ◽  
Injection Pressure ◽  
Fuel Mixture ◽  
Long Distance ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone

Experimental study on macroscopic spray characteristics of a certain type of domestic common rail injectors under the conditions of different injection pressures was carried out through a high-speed digital camera. Furthermore, a fuel dripping phenomenon at the end stage of injection was observed through the high-speed digital camera equipped with a long-distance microscope, and a further analysis of the phenomenon was made. The results show the increase in the injection pressure can evidently enhance spray cone angle and expand the scope of spray field in combustion chamber, which is conducive to air-fuel mixture. The spray cone angle during the development spray shows a double-peak shape. And the long response-time of seating of solenoid valve core that disables the injection cutting off in time is one of factors causing fuel dripping phenomenon.

Experimental investigations of kerosene sprays in pressurized evaporating environments

2018 ◽  
Vol 233 (3) ◽  
pp. 413-427 ◽  
Author(s):  
Tao Liu ◽  
Wei Fu ◽  
Bolun Yi ◽  
Lanbo Song ◽  
Qizhao Lin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Ambient Temperature ◽  
High Speed ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Experimental Investigations ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Ambient Temperatures ◽  
Performance And Emissions

Experiments of kerosene spray with single-hole solenoid injector in the pressurized nonevaporating and evaporating environments, in which the ambient pressure ranges from 1.4 MPa to 4.8 MPa and the ambient temperature includes 300 K, 343 K, and 423 K, are carried out with high-speed Schlieren photography to investigate the breakup regimes and the macro-characteristics like penetration, projected spray area, and spray cone angle. Repetitive experiments are conducted to analyze the penetration repeatability. The comparison between the experimental penetrations and the predicted ones by the existing correlations reveals that the deviations between the experimental data and the predictions rise as the ambient temperature rises. Therefore, a new modified correlation is proposed to predict the penetration of kerosene spray in the nonevaporating and evaporating environments, which fits the experimental data better than the existing correlations. The breakup regimes in primary breakup and secondary breakup are discussed respectively. The projected spray area is analyzed under different ambient pressures at different ambient temperatures. Finally, it is found that the spray cone angle remains almost the same under different ambient pressures after it reduces sharply before 0.5 ms. The macro-characteristics discussed in the present study are important for the performance and emissions of aeronautical engines or diesel engines fuelled by kerosene as a substitution.

Experimental Study on Spray Characteristics of N-Butanol/Acidic Oil/Diesel Blends

2014 ◽  
Vol 1008-1009 ◽  
pp. 1001-1005 ◽  
Author(s):  
Jian Wu ◽  
Yang Hua ◽  
Zhan Cheng Wang ◽  
Li Li Zhu ◽  
Wei Wei Shang
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Cone Angle ◽  
Injection Pressure ◽  
Air Entrainment ◽  
Mixing Ratio ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Spray Penetration

In order to better research on the spray characteristics of biodiesel and n-butanol blends, an experimental study of spray characteristics of different fuel mixtures was investigated in a constant volume vessel using high speed photograph method, and analyzed the influence of different proportions of acidic oil biodiesel and n-butanol on the macroscopic parameters of spray penetration, spray cone angle and so on. The results show that with the increase of acidic oil biodiesel ratio, the air entrainment is weakened, spray penetration gradually increases and spray cone angle decreases under the same injection pressure and back pressure. After adding n-butanol in acidic oil biodiesel and diesel mixture fuel, the surrounding air entrainment is enhanced, and spray front end widen. With the increase of mixing ratio, spray penetration increases first, then decreases. The spray cone angle increases after adding n-butanol, and decreases with the increase of mixing ratio. The results show that adding n-butanol can be used as one of the methods to improve biodiesel spray characteristics.

scholarly journals Spray Analysis and Combustion Assessment of Diesel-LPG Fuel Blends in Compression Ignition Engine

Fuels ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 1-15
Author(s):  
Massimo Cardone ◽  
Renato Marialto ◽  
Roberto Ianniello ◽  
Maurizio Lazzaro ◽  
Gabriele Di Blasio
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
High Pressures ◽  
Cone Angle ◽  
Cetane Number ◽  
Engine Performance ◽  
Exhaust Emissions ◽  
Compression Ignition Engine ◽  
Spray Cone Angle ◽  
Spray Cone

A major challenge for internal combustion engines (ICEs), and diesel engines, in particular, is the reduction of exhaust emissions, essentially nitrogen oxides (NOx) and particulate matter (PM). In this regard, the potential of LPG-diesel blends was evaluated in this work. The LPG and diesel blends were externally prepared by exploiting their perfect miscibility at high pressures. Two diesel-LPG mixtures with 20% and 35% by mass LPG concentrations were tested. In terms of spatial and temporal evolution, the spray characterization was performed for the two blends and pure diesel fuel through high-speed imaging technique. The combustion behavior, engine performance and exhaust emissions of LPG-diesel blends were evaluated through a test campaign carried out on a single-cylinder diesel engine. Diesel/LPG sprays penetrate less than pure diesel. This behavior results from a lower momentum, surface tension and viscosity, of the blend jets in comparison to diesel which guarantee greater atomization. The addition of LPG to diesel tends to proportionally increase the spray cone angle, due to the stronger turbulent flow interaction caused by, the lower density and low flash-boiling point. Because of improved atomization and mixing during the injection phase, the blends have shown great potential in reducing PM emissions, without affecting engine performance (CO2 emissions). The addition of LPG resulted in a significant smoke reduction (about 95%) with similar NOx emissions and acceptable THC and CO emissions. Furthermore, the low cetane number (CN) and high low-heating value (LHV) ensuring leaner air-fuel mixture, and improvements in terms of efficiency, particularly for a blend with a higher concentration of LPG.

scholarly journals CFD simulations of the diesel jet primary atomization from a multihole injector

2017 ◽  
Author(s):  
Charalambos Chasos
Keyword(s):  
High Pressure ◽  
Nozzle Exit ◽  
Cone Angle ◽  
Injection Pressure ◽  
Liquid Jet ◽  
Spray Cone Angle ◽  
Two Phase ◽  
Spray Cone ◽  
Breakup Length ◽  
Jet Breakup

High pressure multi-hole diesel injectors are currently used in direct-injection common-rail diesel engines for the improvement of fuel injection and air/fuel mixing, and the overall engine performance. The resulting spray injection characteristics are dictated by the injector geometry and the injection conditions, as well as the ambient conditions into which the liquid is injected. The main objective of the present study was to design a high pressure multi-hole diesel injector and model the two-phase flow using the volume of fluid (VOF) method, in order to predict the initial liquid jet characteristics for various injection conditions. A computer aided design (CAD) software was employed for the design of the three-dimensional geometry of the assembly of the injector and the constant volume chamber into which the liquid jet emerges. A typical six-hole diesel injector geometry was modelled and the holes were symmetrically located around the periphery of the injector tip. The injector nozzle diameter and length were 0.2 mm and 1 mm, respectively, resulting in a ratio of nozzle orifice length over nozzle diameter L/D = 5. The commercial computational fluid dynamics (CFD) code STAR-CD was used for the generation of the computational mesh and for transient simulations with an Eulerian approach incorporating the VOF model for the two-phase flow and the Rayleigh model for the cavitation phenomenon. Three test cases for increasing injection pressure of diesel injection from the high pressure multi-hole diesel injector into high pressure and high temperature chamber conditions were investigated. From the injector simulations of the test cases, the nozzle exit velocity components were determined, along with the emerging liquid jet breakup length at the nozzle exit. Furthermore, the spray angle was estimated by the average radial displacement of the liquid jet and air mixture at the vicinity of the nozzle exit. The breakup length of the liquid jet and the spray cone angle which were determined from the simulations, were compared with the breakup length and cone angle estimated by empirical equations. From the simulations, it was found that cavitation takes place at the nozzle inlet for all the cases, and affects the fuel and air interaction at the upper area of the spray jet. Furthermore, the spray jet breakup length increases with elapsed time, and when the injection pressure increases both the breakup length and the spray cone angle increase.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.5040

scholarly journals Effect of Low Ambient Pressure on Spray Cone Angle of Pressure Swirl Atomizer

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhengyan Guo ◽  
Yi Jin ◽  
Kai Zhang ◽  
Kanghong Yao ◽  
Yunbiao Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Spray Angle ◽  
High Speed Photography ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer

Pressure swirl atomizers are widely used in gas turbine combustor; this paper is aimed at researching the effect of low ambient pressure (0.1 MPa to 0.01 MPa, lower than an atmosphere) on the spray cone angle of pressure swirl atomizer. The spray angle is captured by high-speed photography; then, an image post program is used to process the spray angle magnitude. A mathematical model of a single droplet’s movement and trajectory based on force analysis is proposed to validate the spray angle variation. The maximum variation of the spray cone angle, which is observed when fuel supply pressure drop through the atomizer is 1 MPa as the ambient pressure decreases from 0.1 MPa to 0.01 MPa, is found to be 23.9%. The experimental results show that the spray cone angle is expected to increase with the ambient pressure decrease; meanwhile, mathematical results agree well with this trend.

Development of a High-Pressure, High-Temperature, Optically Accessible Continuous-Flow Vessel for Fuel-Injection Experiments

2013 ◽  
Author(s):  
Kemar C. James ◽  
Jin Wang ◽  
Zackery B. Morris ◽  
Michael C. Maynard ◽  
Brian T. Fisher
Keyword(s):  
Liquid Phase ◽  
Continuous Flow ◽  
High Speed ◽  
Fuel Injection ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Spray Visualization

The focus of this work was to develop a continuous-flow vessel with extensive optical access for characterization of engine-relevant fuel-injection and spray processes. The spray chamber was designed for non-reacting experiments at pressures up to 1380 kPa (200 psi) and temperatures up to 200°C. Continuous flow of inert “sweep gas” enables acquisition of large statistical data samples and thus potentially enables characterization of stochastic spray processes. A custom flange was designed to hold a common-rail diesel injector, with significant flexibility to accommodate other injectors and injector types in the future. This flexibility, combined with the continuous flow through the chamber, may enable studies of gas-turbine direct-injection spray processes in the future. Overall, the user can control and vary: injection duration, injection pressure, sweep-gas temperature, sweep-gas pressure, and sweep-gas flow rate. The user also can control frequency of replicate injections. There are four flat windows installed orthogonally on the vessel for optical access. Optical data, at present, include global spray properties such as liquid-phase fuel penetration and cone angle. These measurements are made using a high-speed spray-visualization system (up to 100 kHz) consisting of a fast-pulsed LED (light emitting diode) source and a high-speed camera. Experimental control and data acquisition have been set up and synchronized using custom LabVIEW programs. The culmination of this development effort was an initial demonstration experiment to capture high-speed spray-visualization movies of n-heptane injections to determine liquid-phase fuel penetration length (i.e., liquid length) and spray cone angle. In this initial experiment, fuel-injection pressure was ∼120 MPa (1200 bar) and the injection command-pulse duration was 800 μs. At room conditions, liquid length and nominal spray cone angle were ∼170 mm and ∼14.5°, respectively. In contrast, with air flow in the chamber at 100 psi and 100°C, liquid length was considerably shorter at ∼92 mm and spray cone angle was wider at ∼16.5°. Future experiments will include the continuation of these measurements for a wider range of conditions and fuels, extension of high-speed imaging to vapor-phase fuel penetration using schlieren imaging techniques, and detailed characterization of spray properties near the injector nozzle and near the liquid length.

Experimental Study of Airless Spray Jet Breakup at Elevated Temperature and Pressure

2013 ◽  
Vol 393 ◽  
pp. 711-716 ◽  
Author(s):  
Muhammad Yasin Naz ◽  
Shaharin Anwar Sulaiman ◽  
Bambang Ari-Wahjoedi
Keyword(s):  
High Speed ◽  
Water Injection ◽  
Research Work ◽  
Ambient Air ◽  
High Water ◽  
Processing Parameters ◽  
Spray Cone ◽  
Load Pressure ◽  
Breakup Mechanism ◽  
Jet Breakup

The presented research work was focused onto the understanding of the jet behavior of the sprays of heated water during the low pressure atomization process. This task was accomplished using an in-house built intermittently forced liquid spraying system capable of lowering the liquid viscosity and surface tension to a desired value and then atomizing it into a full cone spray patterns in the ambient air surrounding. Using a high speed camera, the jet breakup dynamics were visualized as a function of system input parameters. The analysis of the grabbed images confirmed the strong influence of these processing parameters on full cone spray characteristics. It was also predicted that heated liquids generate a dispersed spray pattern by utilizing the partial evaporation of the spraying medium that is the induction of thermal energy enhances the jet disintegration ability. The spray cone width and angle did not vary significantly whereas the Weber and Reynolds numbers along with other nozzle flow parameters showed an appreciable response to the load pressure and temperature at early stages of water injection. The ultimate objective of the work was to understand and control the airless spray jet breakup mechanism under reduced load pressure and high water temperature.

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