منصة إيفاد العلمية

د. احمد منير الدين فائق

إرسال رسالة

التخصص: الهندسة الميكانيكية

الجامعة: المستنصرية

النقاط:

معامل الإنتاج البحثي

الخبرات العلمية

استاذ مساعد دكتور في كلية الهندسة
مهندس ميكانيك

الأبحاث المنشورة

Multicomponent fuel droplet combustion investigation using magnified high speed backlighting and shadowgraph imaging

المجلة: Fuel

سنة النشر: 2018

تاريخ النشر: 2018-06-01

Liquid-phase dynamics during the two-droplet combustion of diesel-based fuel mixtures

المجلة: Experimental Thermal and Fluid Science

سنة النشر: 2020

تاريخ النشر: 2020-07-01

The liquid-phase processes occurring during fuel droplet combustion are important in deciding the behaviour of the overall combustion process, especially, for the binary fuel droplets. Hence, understanding these processes is essential for explaining the combustion of the binary fuel droplet. However, experimental investigation of such processes is not easily accomplishable due to the very short period of time available for tracking them within the finely small fuel droplet. In the present work, a high speed imaging and subsequent image processing leading to quantitative analysis of the binary fuel droplet combustion including liquid-phase dynamics are performed. Two categories of binary fuels – in which diesel is the base fuel – are prepared and utilized. The first category is biodiesel/diesel and bioethanol/diesel blends, while the second category is the water-in-diesel and diesel-in-water emulsions. Specific optical setup is developed and used for tracking droplet combustion. The resulting magnification of the droplet images is up to 30 times the real size, offering the possibility of droplet interior visualization at high imaging rates up (to 40,000 fps). With the aid of this setup, spatial and temporal tracking of nucleation, bubble formation, puffing, microexplosion, and secondary atomization during the combustion of two adjacent binary fuel droplets are performed. The burning rate constants are evaluated and found to have the same trends as the isolated droplet combustion. However, the ratio of the droplet burning rate constant of the interactive droplet combustion to that of the isolated droplet combustion is higher than unity. This is the same for the nucleation rate within the interacting fuel droplets.

Novel design to enhance the thermal performance of plate-fin heat sinks based on CFD and artificial neural networks

المجلة: Applied Thermal Engineering

سنة النشر: 2023

تاريخ النشر: 2023-01-25

Over the last decades, intensive attentions have been spent for thermal performance enhancement of the heat sinks as a result of the heat dissipation problems in an extremely competitive industry of electronics. In the present work, an efficient thermal design of a plate-fin heat sink with symmetrical half-round hollow pins vertically arranged and subjected to parallel flow is implemented. In particular, a computational fluid dynamic (CFD) analysis was performed for evaluating the thermal performance of the different possible designs, i.e. different values for inside and outside diameters of the attached hollow pins. These limited data points are then fed into a feed-forward back-propagation neural network to predict the base temperature and pressure drop that can be based on to judge the most effective geometry of the hollow pins. Acceding to the obtained results, the difference between neural network simulations and the reference data was less than 1.24 %. This is next followed by a CFD analysis of the pin’s pitch effect on the thermal performance of the studied heat sinks to find the most efficient design. Furthermore, the optimum inner and outer radius of pin and fin’s pitch are 1.08 mm, 1.2516 mm, and 3.6 mm, respectively. Moreover, the accuracy of correlation equations to predict Nusselt number and friction factor is 88.98 % and 88.81 %, respectively. The study has shown that the proposed design shows higher thermal performance of approximately 20 % over the other configurations in the literature while maintaining the bare minimum change in fabrication and implementation. Therefore, this design has a promising potential to enhance the thermal efficiency of the electronic devices.

Droplet Combustion Characteristics of Biodiesel–Diesel Blends using High Speed Backlit and Schlieren Imaging

المجلة: Heat Transfer Engineering

سنة النشر: 2019

تاريخ النشر: 2019-08-27

This work investigates the effect of blending biodiesel with diesel on the combustion of an isolated fuel droplet. Biodiesel blends substituting diesel oil in different concentrations on volumetric basis, in addition to neat diesel and biodiesel, were studied. High-speed Schlieren and backlighting imaging techniques have been used to track droplet combustion. The results showed that partial substitution of diesel oil by biodiesel at the test conditions led to increasing secondary atomization from the droplet, compared to neat diesel or biodiesel fuel droplets. This in turn enhances evaporation, mixing, and then combustion. Additionally, the results showed that biodiesel has a higher burning rate compared to diesel, and that increasing biodiesel in the blend increases the burning rate of the blend. Nucleation has also been traced to take place inside the droplets of the blends. Moreover, flame size (height and width) has been reduced by increasing biodiesel concentration in the blend.

The Impact of Methanol Addition to the Biodiesel-Diesel Blends on the Performance and Exhaust Emissions of the CI Engines

المجلة: Journal of Physics: Conference Series

سنة النشر: 2019

تاريخ النشر: 2019-07-01

One of the major problems in the contemporary world is pollution. The major contribution in this area comes from automobile emissions and industries. Diesel being one of the major fuels is also a major contributor in adding harmful pollutants into the atmosphere. In order to meet the stringent emission norms, the polluting components in the fuels need considerable reduction. Fuel characteristics play a major role in engine efficiency and engine emissions directly or indirectly. In the present work, an experimental investigation of the effect of adding methanol to the diesel-biodiesel blends on the performance and combustion characteristics of the diesel engine has been performed. Three different concentrations of methanol are used; namely 5%, 7%, and 10% of the overall mixture volume, while, biodiesel concentration has been fixed to eliminate its effect on the results. The results revealed that using methanol as an additive to the diesel-biodiesel blends prominently improved brake power, decreased brake specific fuel consumption (BSFC) and increased brake thermal efficiency (BTE) of the engine. CO, HC, and NOx emissions have shown a slight decrease compared to the corresponding neat diesel and diesel-biodiesel at the same loading and engine speed conditions.

Quantitative spray analysis of diesel fuel and its emulsions using digital image processing

المجلة: EPJ Web of Conferences

سنة النشر: 2015

تاريخ النشر: 2015-05-06

In the present work, an experimental investigation of spray atomization of different liquids has been carried out. An air-assist atomizer operating at low injection pressures valued (4 and 6 bar) has been used to generate sprays of (diesel fuel, 5, 10, and 15% water-emulsified-diesel), respectively. A Photron-SA4 high speed camera has been used for spray imaging at 2000 fps. 20 time intervals (from 5 to 100 ms with 5 ms time difference) are selected for analysis and comparison. Spray macroscopic characteristics (spray penetration, dispersion, cone angle, axial and dispersion velocities) have been extracted by a proposed technique based on image processing using Matlab, where the maximum and minimum (horizontal and vertical) boundaries of the spray are detected, from which the macroscopic spray characteristics are evaluated. The maximum error of this technique is (1.5% for diesel spray) and a little bit higher for its emulsions.

Post-Impact Characteristics of a Diesel-in-Water Emulsion Droplet on a Flat Surface Below the Leidenfrost Temperature

المجلة: International Journal of Renewable Energy Development

سنة النشر: 2021

تاريخ النشر: 2021-01-02

Droplet impingement on solid surfaces takes place in a variety of industrial and environmental applications. However, there are still some areas that are not fully comprehended; emulsion droplet impact on a heated surface is one of these areas that require further comprehension. Hence, the present work represents an experimental exploration for spread characteristics of diesel-in-water (DW) emulsion droplet impacting a heated flat plate. Three different emulsions in which water concentration is set to 10%, 20%, and 30% of the overall emulsion content by volume have been tested in addition to the neat diesel. The temperature of the flat plate is varied over the range 20, 40, 60, and 80ºC respectively. Magnified high speed direct imaging and shadowgraphy have been used simultaneously for tracking droplet spread over the heated surface post impact. Droplet spread rate, maximum diameter, rebound height and velocity represent the main evaluated parameters. The results show that the maximum spread diameter is proportional while spread rate is inversely proportional to the increase in plate temperature for all diesel concentrations including the neat diesel. Whereas, droplet rebound height and velocity are found to be more responsive to the variation in diesel concentration than the variation in plate temperature, so they are both minimum in the case of neat diesel and are increasing by the decrease of diesel concentration in the emulsions.

Effect of Temperature Variation on the Fluctuation of a Sessile Bubble Rising in a Stagnant Medium

المجلة: Journal of Physics: Conference Series

سنة النشر: 2021

تاريخ النشر: 2021-12-02

The present work represents an experimental investigation of the flow dynamics and features of a rising isolated bubble within a stagnant water column under variable temperature. The experimental tests have been carried out using high speed imaging with backlighting. Five different values of the water temperature (namely 10, 20, 30, 40, and 50°C) have been implemented during the experiments. The studied features are the bubble size (diameter and circumference), bubble shape (sphericity and aspect ratio), bubble rising velocity, in addition to the bubble zigzag motion features (angle, maximum horizontal diameter, velocity, and occurrence time portion). The obtained results showed that as the temperature increases, the degree of bubble zigzag motion from its vertical path increases, which means the flow of the bubble becomes less stable. Bubble diameter is shown to be irresponsive to temperature for small value increase, whereas, for greater temperature magnitudes (from 30 to 50°C) it is shown to be proportional. All other features are shown to be proportional to temperature variation. The zigzag motion features are also shown to be proportional to water temperature variation except the average occurrence time is inversely proportional to this change.

THE EFFECT OF DIESEL-ALCOHOL BLENDS ON THE COLDSTART COMBUSTION OF A COMPRESSION IGNITION ENGINE

المجلة: Journal of Engineering and Sustainable Development

سنة النشر: 2018

تاريخ النشر: 2018-03-01

The present work represents an experimental investigation of the effect of blending diesel fuel by alcohol on the cold-start combustion characteristics of the compression ignition engine. The studied characteristics are the CO2, CO, and HC concentrations in the exhaust gases, in addition to the mixture Air/Fuel ratio, exhaust temperature, and engine noise levels. The experimental work has been carried out using a 4-stroke, single-cylinder compression ignition engine at different blending ratio values. These values are 0%, 10%, 20%, and 30% by volume of alcohol concentration with respect to the total mixture concentration. The engine has been tested under two rotational speeds (1800 and 2000 r.p.m). Two alcohols have been used in the experiments, these are ethanol and methanol. The obtained results showed that blending diesel fuel by alcohol has a positive effect on engine exhaust results during the cold-starting period. And that the results obtained from the ethanol blends are better than those obtained from the corresponding methanol blends. It is shown also that the 10% blending ratio for both ethanol and methanol blends is almost the optimum blending ratio, according to the results.

ENGINE COLD START COMBUSTION AND ITS EFFECT ON EXHAUST EMISSIONS

المجلة: Gulf University Journal

سنة النشر: 2010

تاريخ النشر: 2010-12-01

The present work represents an experimental study of the effect of engine cold starting period on the exhaust gases resulted from combustion, where a 4-stroke, single-cylinder, compression ignition engine have been tested at rotational speed values of (2000, 2500, 3000, and 3500 r.p.m), with operation time values of (0, 5, 10, 15, 20, and 25 minutes) after starting. Curves relating exhaust gases (CO2, CO, HC, and O2) to the cold starting period have been obtained. These curves showed that cold starting period (about 15 minutes) has a great effect on those emissions, where theri behaviors are unstable at this period. Break power is also shown to vary with engine cold starting.