Emad Elnajjar

Combustion of waste chocolate oil biofuel in a diesel engine

An experimental study has been carried for almost first time to use methyl esters derived from waste chocolate oil produced from chocolate industry, in an indirect injection diesel engine. Effects of engine speed, engine load output, injection timing of the biofuel and the blend ratio with pure diesel fuel on the engine output torque, combustion noise (maximum pressure rise rate), maximum pressure and maximum heat release rate have been studied. Raw waste oil extracted from the industrial process to produce chocolate has been used to produce the biofuel and its physical and chemical properties have been measured and performance of diesel engine combustion has been evaluated in a Ricardo E6 research engine. It has been found that the biofuel (chocolate oil methyl ester) properties are almost similar to that of diesel and the engine performance was similar to diesel engine running on pure diesel fuel. There is no need to modify the engine when this biofuel is used.

Measurement and Modeling of Confined Jet Discharged Tangentially on a Concave Semicylindrical Hot Surface

The paper investigates experimentally and numerically the heat transfer augmentation from a semicircular heated surface due to confined slot-jet impingement. For different Reynolds numbers, the average and local Nusselt numbers are calculated by reporting the heater thermal image obtained by an infrared camera, the inlet and outlet flow temperature via thermocouples, the flow rate via rotameter, and the pressure drop across the inlet and outlet flow via pressure transducers. The single enclosed jet flow is used to create a single cyclone inside the internal semicircular channel to promote the heat transfer at different jet Reynolds numbers (Rejet = 1000–5000). Three turbulence models, namely, the standard k – ɛ, k – ω and the Reynolds stress model (RSM) have been investigated in the present paper by comparing Nusselt number and normalized pressure drop distribution against the experimental data, helping ascertain on the relative merits of the adopted models. The computational fluid dynamics results show that the RSM turbulent model reasonably forecast the experimental data.

Diesel Engine Performance and Emission Under Hydrogen Supplement

This experimental study reports the behavior of diesel engine while being supported by hydrogen supplement. Hydrogen supplement is added through the air intake manifold at the atmosphere condition (0 °C and 101.325 kPa). The study reports the hydrogen supplement effect on the combustion characteristics, engine performance, emission and fuel consumption. The hydrogen supplement is varied by increment of 2 LPM while keeping the engine under fixed output power condition (torque of 14.7 N-m and speed of 1,100 rpm). In order to keep the engine output power fixed, the diesel fuel consumption is reduced and the hydrogen fuel consumption e hydrogen flow rate. For same power condition (torque and speed), the study shows that hydrogen can be used to reduce diesel fuel consumption however this comes on the expense of increasing of NOx emission. The main finding of this study is that compression engine with hydrogen supplement and diesel as the primary fuel starts knocking when hydrogen form 34 % the output power contribution (or 19 % as mass ratio between hydrogen to diesel).

Feasibility of Vortex Tube Air-Conditioning System

This paper investigates the feasibility of using vortex tube as air-conditioning device. Series of experiments are conducted to evaluate the design parameters and calculate the performances of counter-flow Ranque–Hilsch vortex tube (RHVT). The study is conducted for different inlet pressures conditions, number of nozzle inlets, vortex chamber depth and thermal insulation condition. The vortex tube performance is investigated by measuring temperatures, pressures and mass flow rates for the inlet and hot/cold exits. It is found that vortex tube has very coefficient of performance which make it inadequate to compete with conventional air conditioning system.Copyright

The Potential of Using Raw Jojoba Oil as Fuel in Furnaces

There is a constant need for coming up with new and alternative energy sources that are sustainable and at the same time environment friendly. Many research studies have already been conducted to fulfill the above target and addressed the use of plants-based oils in internal combustion engines. Less emphasis however was directed to the use of such oils in open combustion systems such as furnaces and boilers. The present study considers the potential of using green energy sources such as raw jojoba oil with minimal pretreatment as a sole fuel or alternatively as fuel supplements for furnaces. Blends of raw jojoba oil and diesel, with different proportions were burned in a small cylindrical furnace under different air flow conditions. The studied range of the jojoba oil proportions (on mass basis) in the liquid blends is from 20 to 60 %. More jojoba in the liquid mixture showed difficulty in sustaining a self-supporting flame due to the low volatility and high viscosity of raw jojoba oil. Moreover, the performance of the furnace with 20 % jojoba in the liquid fuel mix shows only small difference from performance on Diesel only. This suggests that about 20 % of Diesel can be replaced with raw jojoba with no significant loss of the thermal performance. More unburned species are emitted as the jojoba content in the fuel blend increases.

Using PCM Implanted in Building Material for Thermal Management: One Versus Seven Days Assessment

The objective of this work is to investigate numerically the thermal analysis of capacitive insulators bricks containing an organic phase change material (PCM) in United Arab Emirate (UAE) hot climate. PCM Latent heat of fusion is secondhand to reduce the heat loads fluctuation and the peak time shifting, which in turn reduces the consumed energy for cooling and therefore reduce green gases emissions. An average of one verses 7 days analysis were performed to account for the cyclic behavior of the PCM in the building material. The study focus on demonstrating the contradictory and deceiving results which can be withdrawn from each analysis.

Effect of Stabilized Water-Diesel Emulsions on External Combustion Characteristics

This study presents an experimental investigation of emulsified fuels with water content of 10%, 20% and 30% by volume, using a small furnace under steady combustion conditions. Pure diesel is used as a baseline in the conducted external combustion for comparison purposes. The study found that water content in the emulsion has strong impact on the flame temperature, the flame heat release and the combustion efficiency. The 20% water-diesel emulsion showed a lower flame temperature and higher combustion efficiency. Using the proper water-diesel emulsion, 20%, the heat release rate of the emulsified fuels is comparable to the one obtained in the pure diesel case. The highest flame temperature and heat flux transfer to water jacket is achieved at pure diesel (0% water content). The optimum water content in diesel emulsion strongly depends on the liquid fuel nozzle design.Copyright

Optimal Parametric Model for Vortex Tube Using DOE

In this study, a vortex tube geometric parametric model will be developed and the parameters will be considered as factors that affect the performance of a vortex tube. SolidWorks is used to generate parametric models; Minitab is used for Design Of Experiments (DOE) combination setups. A 3D printer is used to produce a physical model of the vortex tube to fit each of the DOE combinations. The study reports the effect of different geometric parameters on the cooling/heating load and the outlet temperature. The geometric parameters are investigated by measuring temperatures, pressures and mass flow rates for the inlet and hot/cold outlet flow. Two key factors were considered, namely mass fraction and angle of nozzle. Response factors analyzed are the maximum hot temperature (THMax) and the minimum cold temperature (TCMin).Copyright

Effect of Dual Fuel Engine Parameters and Fuel Type on Engine Noise Emissions

Investigating experimentally the effects of different fuel types and engine parameters on the overall generated engine noise levels. Engine parameters such as: Engine speed, Injection timing angle, engine loading, different pilot fuel to gases fuel ratio and engine compression ratio. Engine noises due to combustion, turbulent flow and motoring were reported in this study by direct sound pressure level SPL (dB) measurements and compared to the maximum cylinder pressure rise rate with respect to the engine crank angle (dP/dθ)max . Experimental procedures conducted using a Ricardo diesel version variable compression research engine. The study was conducted for three different fuels: single diesel fuel, and dual fuel engine that uses LPG or natural gas. The study for each fuel type covered the following operating parameters range, engine speed from 20–28 rev/sec, injection timing form 20 to 45° BTDC, compression ratio from 16 to 22, load range 2 to 14 N.m, and ratio of pilot to gaseous fuel from 0 to 10%. The study reported the location (crank angle) corresponding to maximum cylinder pressure and max pressure rise rate. Results from testing dual fuel engine with varying design and operating parameters are presented and discussed. The present work reported higher SPL (dB) generated from burning a dual fuel compared to burning diesel fuel only.Copyright