Mohy S. Mansour

• Ph.D.
• Professor (Full) at Cairo University

The present study is an extension of our earlier mixing field investigation in partially premixed flames. In the current work, the link between the mixing field and flame structure, and hence flame curvature and surface density are experimentally studied. The flame structure is captured using a high-speed OH-PLIF technique, whereas the crosswise mi...

Turbulent flames with compositionally inhomogeneous mixtures are commonly used in many combustion systems. In this work, turbulent planar jet flames issued from a concentric flow slot burner, CFSB, were used to study the impact of mixture inhomogeneity near the flame sheet. The CFSB burner can control the mixing in-homogeneity by changing the mixin...

This study is geared toward generating highly stabilized partially premixed flames at various levels of turbulence and partially premixing. Therefore, with the help of the laser-induced breakdown spectroscopy (LIBS) technique, a new burner was constructed and employed to quantitatively estimate the mixture equivalence ratio (Φ) within the flame. Tw...

In most practical combustion devices, the actual combustion process occurs within different mixture in-homogeneity levels. Investigating the mixture fraction field upstream of the reaction zones of these flames is an essential step toward understanding their structure, stability, and emission formation. In this study, the mixture fraction fields we...

The scope of this study was twofold: to define the most suitable Egypt's biodiesel source, and to assess the impact of this biodiesel source with the addition of carbon nano additives on diesel engine performance and emissions. Environmental Key Performance Indicators were used as metrics to identify the appropriate biodiesel source with respect to...

Enhancement of biogas combustion characteristics will increase the possibility of the direct utilization of such an eco-friendly fuel in practical combustors. We report a full study of biogas combustion under partially premixed mode to investigate the stability of biogas free-jet flames using a concentric flow slot burner was used to evaluate the b...

The co-combustion of sewage sludge (SS) and biomass is promising for achieving energy recovery and compensating for individual feedstock disadvantages. However, the emission of nitric oxide (NOx) during this process is of concern, but no relevant study has focused on this. In this study, the release characteristics of NOx during co-combustion of SS...

Turbulent flames with compositionally inhomogeneous mixtures are common in many combustion systems. Turbulent jet flames with a circular nozzle burner were used earlier to study the impact of inhomogeneous mixtures, and these studies showed that the nozzle radius affects the flame stability. Accordingly, planar turbulent flames with inhomogeneous t...

Tar pollution is the most serious problem hampering the application of biomass gasification. Microwave exhibits unique effects for treating biomass tar and thus have attracted considerable attention. However, as an energy-intensive technology, the optimal operating parameters of microwave have not been developed, and the energy feasibility remains...

A double perturbation analysis is performed to the Darcy–Brinkman equations for a two‐dimensional slider bearing with homogeneous surface roughness. The surface roughness is parallel to the flow direction. The stationary random model is used to mimic the surface roughness of the slider bearing walls. The slider is filled with a porous medium. The e...

Biogas combustion is a very essential topic for the development of many industrial combustion systems and engines. This fuel can replace current fossil fuels used in burners, engines, and many other applications. Understanding the combustion characteristics of this fuel and its stability in highly turbulent flames of practical interest is the aim o...

Many Nanoparticles (NPs) were reported to significantly enhance the production of biogas from the anaerobic digestion of organic wastes. Herein, two types of NPs (Ni-Ferrite and Ni-Co-Ferrite) were synthesized using the co-precipitation method and characterized using X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRT...

Background The early complete morphological remission (CR) after induction chemotherapy is a major independent prognostic factor for both achievements of CR and long-term outcome in acute myeloid leukemia. we studied the correlation between the serum IL-6 levels and the early morphological CR aiming to use serum level of IL-6 instead of invasive pa...

Biogas combustion is very essential topic for the development of many industrial combustion systems and engines. This fuel can replace current fossil fuels used in burners, engines and many other applications. Understanding the combustion characteristics of this fuel and its stability in highly turbulent flames of practical interest is the aim of t...

The creation of a more stable flame along with the extension of flammability limits under lean mixture combustion was the main motivation to develop a new burner design, which has been investigated in this research. The current burner configuration was utilized to create a wide range of higher turbulent intensities and to produce different degrees...

A new burner was developed in order to achieve very stable lean flames at lower equivalence ratio and higher level of turbulence intensity. The air-fuel mixing process of the current burner was controlled either by using different levels of partially premixed or by changing the turbulence generator disk slit diameter, ds. Initially, the distributio...

Partially premixed combustion is characterized by mixture fraction inhomogeneity upstream of the reaction zone and occurs in many applied combustion systems. The temporal and spatial fluctuations of the mixture fraction have tremendous impact on the combustion characteristics, emission formation, and flame stability. In this study, turbulent partia...

Partially premixed turbulent flames with non-homogeneous jet of propane were generated in a concentric flow conical nozzle burner in order to investigate the effect of the coflow on the stability and flame structure. The flame stability is first mapped and then high-speed stereoscopic particle image velocimetry, SPIV, plus OH planar laser-induced f...

Combustion of turbulent inhomogeneous mixtures of air and fuel is common in many practical systems providing improved stability for both gaseous and liquid fuels. Understanding the structure and stability of turbulent flames in this mode has been the aim of many research groups who employed special burner designs to control the fuel and air mixing...

Considerable interest has been paid to laser-induced breakdown in liquid because of its wide application to medical issues of the eye and environmental monitoring. Therefore, the present work aims to study the phenomena of LIB in bulk distilled water generated in laser-induced breakdown spectroscopy (LIBS) experiment. The effect of experimental par...

Experimental optical tests were carried out in two concentric tubes burner, to obtain a comprehensive understanding of the turbulence level effects on flame kernel propagation in partially premixed flames. Two ND-YAG lasers with first and second harmonic wavelengths were employed for laser ignition and flow field velocity measurements, respectively...

This paper applies the Brinkman-extended Darcy model to investigate the flow in micro-channels between two parallel corrugated walls. The stationary random model is used to imitate the stochastic surface roughness of the walls. The channel is filled with a sparse porous medium. A boundary perturbation method is used to obtain the stochastic volume...

The mixing field is known to be one of the key parameters that affect the stability and structure of partially premixed flames. Data in these flames are now available covering the effects of turbulence, combustion system geometry, level of partially premixing and fuel type. However, quantitative analyses of the flame structure based on the mixing f...

Partially premixed combustion is one of the common combustion modes for many practical combustion systems where the mixture is classified as nonhomogeneous. The available experimental data show that the nature of mixing affects significantly the flame stability and structure of partially premixed flames at the same level of turbulence and local sto...

The Ninth Mediterranean Combustion Symposium, jointly co-sponsored by the Combustion Institute and the International Centre for Heat and Mass Transfer, was held in Rhodes, Greece, in June 2015. It was built on the success of eight previous meetings held in Antalya, Turkey in June 1999, in Sharm El-Sheikh, Egypt in January 2002, in Marrakech, Morocc...

The stability limits, the stabilization mechanism, and the flow field structure of highly stabilized partially premixed methane flames in a concentric flow conical nozzle burner with air co-flow have been investigated and presented in this work. The stability map of partial premixed flames illustrates that the flames are stable between two extincti...

Partially premixed combustion is one of the common modes for many practical combustion systems where the mixture is not homogenous and characterized by fluctuations in mixture fraction. This mode covers a wide range between fully premixed and non-premixed combustion modes. Quantitative description of the several regimes in partially premixed mode i...

This work presents experimental investigation of turbulent partially premixed flames (PPF’s) stabilized within a concentric flow conical nozzle (CFCN) burner with a turbulence generator. The burner stability limit is investigated. In addition, the flow and temperature fields are measured above the conical nozzle exit using 2D PIV and fine wire ther...

Laser Induced Breakdown Spectroscopy (LIBS) technique has been applied to quantitative mixture fraction measurements in flames. The measured spectra of different mixtures of natural gas and air are used to obtain the calibration parameters for local elemental mass fraction measurements and hence calculate the mixture fraction. The data are compared...

The Eighth Mediterranean Combustion Symposium, jointly co-sponsored by the Combustion Institute and the International Centre for Heat and Mass Transfer, was held in Çe¸sme, Izmir, Turkey, on September 8–13, 2013. It was built on the success of seven previous meetings held in Antalya, Turkey, in June 1999; in Sharm El-Sheikh, Egypt, in January 2002;...

Flame development, propagation, stability, combustion efficiency, pollution formation, and overall system efficiency are affected by the early stage of flame generation defined as flame kernel. Studying the effects of turbulence and chemistry on the flame kernel propagation is the main aim of this work for natural gas (NG) and liquid petroleum gas...

Flame development, propagation, stability, combustion efficiency, pollution formation, and overall system efficiency are affected by the early stage of flame generation defined as flame kernel. Studying the effects of turbulence and chemistry on the flame kernel propagation is the main aim of this work for natural gas (NG) and liquid petroleum gas...

Flame kernels in spark-ignited combustion systems dominate the flame propagation and combustion stability, performance and emissions. The aim of the present work is to investigate the flow field associated with flame kernel propagation history in partial premixing natural gas turbulent flames. The main parameters under investigation are the degree...

Many practical combustion systems are based on the mode of partially premixed flames where the interaction between lean and rich pockets improves the flame stability. In our recent work a highly stabilized concentric flow conical nozzle burner has been designed and developed for partially premixed flames. Flow field, temperature and OH radical meas...

The stabilization characteristics and local extinction structures of partially premixed methane/air flames were studied using simultaneous OH-PLIF/PIV techniques, and large eddy simulations employing a two-scalar flamelet model. Partial premixing was made in a mixing chamber comprised of two concentric tubes, where the degree of partial premixing o...

A passive, Q-switched pulsed, Nd:YAG laser system was designed and built, which can provide a potential compact robust laser source for portable laser induced breakdown spectroscopy systems.The developed laser system operates at 1064 nm. Each laser shot contains a train of pulses having maximum total output energy of 170 mJ. The number of pulses va...

For better understanding of turbulence, the geometry of turbulent structures in turbulent jet flow should be analyzed. The aim of the present work was to experimentally verify the dissipation element theory on highly resolved two-dimensional measurements turbulent jets using Rayleigh scattering technique. The statistical analysis of the characteris...

he flame kernel propagation is believed to be influenced by many operating parameters such as mixing level, turbulent intensity, and the mixture equivalence ratio. The purpose of this study is to investigate the effect of the mixture equivalence ratio and turbulence intensity on the flame kernel and flow field interlinks in partially premixed natur...

Rayleigh scattering is used to topographically produce 2D images to obtain the concentration distribution in a turbulent shear flow. Based on the new technique, the turbulent regions are subdivided into dissipation elements. The geometry of these elements is parameterizing by the linear distance between their extremal points and their scalar struct...

For better understanding of turbulence, the geometry of turbulent structures in turbulent jet flow should be analyzed. The aim of the present work was to experimentally verify the dissipation element theory on highly resolved two-dimensional measurements turbulent jets using Rayleigh scattering technique. The statistical analysis of the characteris...

Design of laser cavities is a complicated process. It includes several optical, geometrical and material parameters. Computer Aided Design of laser cavities reduces the time and effort required to reach the optimum design. In this paper an accurate and fast three dimensional CAD model for simulating solid-state laser systems is developed. Numerical...

Simulation and modeling of the reflectivity and transmissivity of the multilayer DBR of VCSEL, as well as inside the active region quantum well are analyzed using the characteristic matrix method. The electric field intensity distributions inside such vertical-cavity structure are calculated. A software program under MATLAB environment is construct...

Experiments are carried out on partially premixed turbulent flames stabilized in a conical burner. The investigated gaseous fuels are methane, methane diluted with nitrogen, and mixtures of CH4, CO, CO2, H2 and N2, simulating typical products from gasification of biomass, and co-firing of gasification gas with methane. The fuel and air are partiall...

Level structure, oscillator strengths, and transition probabilities are evaluated for 1s2 2s2 2p6 3s2 3p6 3d10, 1s2 2s2 2p6 3s2 3p6 3d9 41 (1=0,1,2,3,4), 1s2 2s2 2p6 3s2 3p5 3d10 41 (1=0,1,2,3,4), and 1s2 2s2 2p6 3s1 3p6 3dl0 41 (1=0,1,2,3,4) states in W46+. The calculations are carried out using COWAN code and are compared with other results in th...

Attosecond high harmonic pulses: generation and characterization / C. H. Nam and K. T. Kim -- High power lasers and interactions / C. Chatwin and R. Young -- Laser accelerators / L. M. El-Nadi ... [et al.] -- Energy levels, oscillator strengths, lifetimes, and gain distributions of S VII, CI VIII, and Ar IX / Wessameldin. S. Abdelaziz and Th. M. El...

It is now a fact that focusing an intense ultra short laser pulse onto a gas jet or thin targets, generates energetic collimated electrons or ions forming ultra short beams of energies > 100 MeV. The different mechanisms to explain such laser accelerated electrons or ions will be discussed. Data obtained by recent experiments will be presented. We...

Aims The aims of this survey were firstly to determine the work of a Multidisciplinary New Baby Clinic for infants with cleft lip and/or palate. Secondly to compare our clinic setup with other cleft centres in the UK and Ireland. Methods A retrospective review was undertaken of case notes and correspondences regarding all of the 79 new patients see...

The structure and dynamics of a turbulent partially premixed methane/air flame in a conical burner were investigated using laser diagnostics and large-eddy simulations (LES). The flame structure inside the cone was charecterized in detail using LES based on a two-scalar flamelet model, with the mixture fraction for the mixing field and level-set G-...

The chaotic optical communication systems are based on the synchronization between the transmitting and receiving chaotic laser diodes. The performance of the system is determined by the bit error rate which can result from either the synchronization deviation or the desynchronization bursts. The time required for resynchronization results in loss...

One of the most recently applied laser-based techniques in combustion environment is the laser-induced breakdown spectroscopy (LIBS). The technique has been extensively and successfully applied to elemental concentration measurements in solids and liquids. The LIBS signal is much weaker in gases and hence more work is required for quantitative meas...

Low swirl burner provides stable lifted flames for fundamental studies of flame structure and turbulence/chemistry interaction in well defined boundary conditions. In the present study the stability characteristics of the burner have been investigated with four tangential jets at the same stoichiometry as the main jet. Two different burner nozzles...

Flame kernels in spark ignited combustion systems dominate the flame propagation and combustion stability and performance. They are likely controlled by the spark energy, flow field and mixing field. The aim of the present work is to experimentally investigate the structure and propagation of the flame kernel in turbulent premixed methane flow usin...

There are many non-linear interaction factors responsible for the performance of the laser cutting process. Identification of the dominant factors that significantly affect the cut quality is important. The present research aims to evaluate the CW ND:YAG laser cutting parameters (the gas pressure, laser power, and scanning speed) for 1.2 mm thick u...

There are many non-linear interaction factors responsible for the performance of the laser cutting process. Identification of the dominant factors that significantly affect the cut quality is important. In the current research, the gas pressure, laser power and scanning speed were selected as the cutting parameters. Effect of the cutting parameters...

Flame stability and mean structure of partially premixed flames have been investigated under the effect of the level of partial premixing and nozzle cone angle. The stability curves and maps of the mean flame structure based on temperature and CO and O2 concentrations measurements in some selected partially premixed flames in the thin reaction zone...

Detection and imaging of multi-reaction zones is an essential tool for understanding the detailed structure of complicated flames. In this work a combined 4-camera technique is presented for multi-reaction zones imaging. The technique combines highly advanced laser-based diagnostics tools, namely Rayleigh scattering, laser-induced predissociation f...

The structure and stabilization mechanism of turbulent lifted non-premixed hydrocarbon flames have been investigated using combined laser imaging techniques. The techniques include Rayleigh scattering, laser induced predissociation fluorescence of OH, LIF of PAH, LIF of CH2O, and planar imaging velocimetry. The geometrical structure of multi-reacti...

The flow field and reaction zone structure at the stabilization point of turbulent partially premixed lifted methane flames have been investigated based on advanced laser-based imaging techniques. Planar imaging velocimetry technique, PIV, is used for the flow field and laser induced predissociation fluorescence technique, LIPF, is used for OH radi...

The stability characteristics of partially premixed turbulent lifted methane flames have been investigated and discussed in the present work. Mixture fraction and reaction zone behavior have been measured using a combined 2-D technique of simultaneous Rayleigh scattering, Laser Induced Predissociation Fluorescence (LIPF) of OH and Laser Induced Flu...

Fractal analyses have been conducted to investigate flame-front wrinkling of turbulent premixed Bunsen flames. Emphasis is placed on the geometric interpretation of measured fractal parameters and their relationship with parameters used in current combustion models. The outer cutoff scale is found to be four times the integral length scale of flame...