I would like to express my gratitude to all those who helped me in completing the thesis. First of all I want to thank Almighty God for giving me strength and courage to do research. I would like to thank my parents and siblings for their endless love, support and encouragement.
Finally I would like to thank all my friends Zaid, Sumit, Rajesh, Sammed, Harilal, Rakesh and Anil for supporting me to finish my work. For the solution of the aforementioned problem, the study of the air-fuel mixture is important, and this mixture is directly affected by the amount of injected fuel, the time of injection, spray area, spray penetration length, etc. The purpose of this study is to develop a method to study the spray characteristics of the iso-octane and n-butanol mixture (B0, B5, B10 and B20) in a constant volume combustion chamber.
The pressure and temperature of the room are increased by the pre-combustion of the mixture of acetylene and air. Since butanol is gaining more and more interest for SI engine fuel, the present study will help the engine researcher to understand the in-cylinder phenomenon.
- Current Energy Scenario and Need for Alternative fuel
- Life Cycle Emissions
- THE VISION AND GOALS of Biofuel Policy of India
- LITERATURE REVIEW
- Gasoline Direct Injection Engine
- Types of engine system of SI (spark ignition) engine
- OIL RECOVERY PROCESS
Such an unforeseen escalation in oil prices puts a strain on the economies of developing countries, as these countries are heavily dependent on crude oil imports. In addition, oil from Petrol meets approximately 95% of transport fuel needs, and demand is steadily increasing. Domestic crude oil can meet only about 23% of the demand and the rest is met by imported crude oil.
Also, to ensure that a minimum level of biofuel to be readily available in the market to meet demand. Blending levels prescribed in relation to bio-diesel are intended to be recommendations in the near term. In the year 1876, the German inventor Nicolaus Otto gave one of the greatest inventions in history viz.
From the above equation it is clear that the efficiency of the Otto cycle is directly proportional to the compression ratio. In the gasoline engine, the air-fuel mixture is prepared both inside the cylinder and outside the cylinder.
Fundamentals of Optical Techniques and Liquid spray
Optical Diagnostic Techniques
- Concept of Schlieren, Shadowgraph and Mie scattering
Schlieren image analysis is based on beam deflection (but not displacement), while the shadow plot takes into account both beam deflection and displacement. As we know, any light source that falls on a transparent object or on a test area is refracted, bent, deflected and scattered from their original path. After undergoing refraction by angle ϵ, it reaches the screen displaced by distance ∆a from its original path.
This basic concept is the same for the schlieren system as well, whose schematic diagram is shown in Figure 6. But the main difference is the use of knife eggs, which block further refracted light rays, resulting in more contrast in the image. In the case of mie scattering, the light rays fall on the spray, then it is scattered, and the scattered light reaches the camera.
FUNDAMENTALS OF LIQUID SPRAY
- Spray Regimes
- Spray Atomization
- Breakup Regimes
However, due to the liquid-to-gas density ratio, the mass fraction of the liquid phase can still be significant. The very thin or dilute spray regime is ultimately characterized by both volume and mass fractions of the liquid phase being negligible compared to those of the gas phase. At the other extreme, in the dilute spray regime, the droplet behavior can be calculated based on relationships for an isolated droplet with good accuracy.
There is still some mass, momentum and energy transfer between the droplets and the gas phase, but the influence the droplets have on the gas phase is very small. In the intermediate thin spray regime, the liquid phase is still responsible for a noticeable mass fraction, as noted above. An example of this is the reduced drag forces on the droplets that are in the wake of the spray tip and are therefore slowed down.
This process seems reasonable, since in high-pressure injection systems the breakup of the liquid phase into small droplets starts very close to the nozzle opening. Thus, the effect of an intact liquid core on the gas phase is extremely small compared to the effect that dispersed liquid droplets have on the gas phase in the entire spray. The first type of breakdown occurs at or in close proximity to the injection nozzle orifice.
The primary breakup describes the breakup of the intact liquid phase into first ligaments and droplets. The primary breakup of liquid jets at the nozzle exit can be caused by a combination of three mechanisms: turbulence within the liquid phase, implosion of cavitation bubbles and aerodynamic forces acting on the liquid jet. This generates a high level of turbulence within the liquid phase which has a destabilizing effect on the jet as soon as it leaves the nozzle.
According to Bernoulli's law, this causes a decrease in the static pressure, and locally the static pressure can decrease to a value as low as the fuel vapor pressure. Cavitation bubbles are swept from the nozzle into the combustion chamber where they explode and contribute to spray breakup. The third mechanism is that the relative velocity between the liquid and gas jet results in aerodynamic forces acting on
Experimental set up
- Description of the constant volume vessel
- Experimental Set up
- Focused Shadowgraph – Experimental Setup
- Mie Scattering – Experimental Setup
- Experimental Procedure and Test Matrix
- Image Processing
- Calculation of Penetration Length
- Some Special Functions in Matlab for Image processing
- Image Processing Procedure
The fuel pump is a separate unit placed next to the frame of the experimental setup. First parabolic mirror is placed 914.4 mm from the light source to collimate the light beam. Second parabolic mirror is placed after the test section to decollimate the light beam with a focus at the focal point.
A plane mirror is used to reflect the collimated light beam from the first parabolic mirror to the spray chamber. Optical components are supported on the adjustable mounts, providing the flexibility to easily align even minor misalignments. Then a cylindrical lens is used to make the laser beam into a conical shape and after that diffuser is used, the light rays basically go to the spray chamber and hit the spray which further scatters and the scattered light.
If there is a small leak at this high pressure, it can be seen by the smell of the combustion products, which will spread inside the room if there is any leakage after the combustion. To study the effect of the pressure, five different pressure ratios and 15 bar) were chosen. All boundary points tracked by the matlab code are selected and only the points to the right of the injection points are isolated.
The steps below are for illustrative purposes only and are performed for one particular image. Determine the row and column coordinates of a pixel on the edge of the object you want to trace. As required arguments you must provide a binary image, the row and column coordinates of the starting point, and the direction of the first step.
Display the original image in grayscale and use the coordinates returned by bwtraceboundary to draw the boundary on the image. For certain objects, you need to be careful when choosing the boundary pixel you choose as the starting point and the direction you choose for the first step parameter (north, south, etc.). For example, if an object contains a hole and you select a pixel on a thin part of the object as the starting pixel, you can trace the outer boundary of the object or the inner boundary of the object.
For filled objects, the direction you choose for the first step parameter is not so important. To illustrate, this figure shows the tracked pixels when the initial pixel is on a thin part of the object and the first step is set to north and south.
Results and Discussions
It clearly shows that at the ambient temperature and pressure (at room temperature and atmospheric pressure) the vapor penetration length is more than at elevated temperature and pressure. This can be explained as the pressure increases, it does not allow the steam to travel faster. Therefore, the pressure effect for the condition of the surroundings and at 7 bar is more significant than 7 bar and 15 bar.
First the mean of three experiments is found then for the positive error bar the mean pressure is subtracted from the maximum of the three pressures and the negative error bar is defined as the minimum of the three experiments minus the mean pressure. The figures given and 25 show the liquid penetration length versus time for all mixtures at various pressures. It clearly shows that the penetration length falls below the error bar of other mixtures, which can be said that the penetration length is the same for all the mixtures.
So the average of the penetration length is basically the average of the penetration length from 1ms to 3.8ms. Here it is observed that the liquid penetration length is the same for all mixtures at a certain pressure and as the pressure increases, the penetration length decreases. Further analysis of change in vapor pressure of iso-octane/n-butanol mixture with respect to composition needs to be carried out.
