M.R. Heikal

• Head of Department at University of Brighton

The study of turbulence characteristics in two-phase flows always remained challenging due to its chaotic nature. The hidden coherent structures are dynamically important and play significant role to define their macro-characteristics. Here, we present Linear Stochastic Estimation (LSE)-based approach combined with Proper Orthogonal Decomposition (...

Puffing/microexplosion potentially increases atomization and enables better air–fuel mixing in sprays, thereby improving combustion. In this paper, we have investigated the physics leading to puffing and microexplosion in fuel droplets and identified factors such as droplet detachment modes and droplet-air interaction that influence puffing/microex...

RICARDO-VECTIS CFD simulation of the in-cylinder air flow was first validated with those of the experimental results from high-speed particle image velocimetry (PIV) measurements taking cognisant of the mid-cylinder tumble plane. Furthermore, high-speed fuel spray measurements were carried out simultaneously with the intake-generated tumble motion...

There is an upsurge in the drive for better understanding of the processes, which control the combustion in modern engines. Large-scale intake generated flow structures, such as swirl and tumble, are known to have a significant effect on the combustion behaviour and have been widely studied by the automotive research community. Traditionally, the s...

In this paper we present the basic concepts of operations of a hybrid liquid nitrogen and internal combustion engine currently under development by Ricardo Innovations, Dolphin N2 and the University of Brighton, the CryoPower recuperated split cycle engine (RSCE). The engine is based on a new split-cycle combustion concept utilising isothermal comp...

A new analytical solution to the one-dimensional transient heat conduction equation in a composite spherically symmetric water-fuel emulsion droplet, suspended in a hot gas, is obtained. The Robin boundary condition at the surface of a droplet and conditions at the fuel-water interface are used. A water sub-droplet is assumed to be located at the c...

Producing reliable in-cylinder simulations for quick-turnaround engine development for industrial purposes is a challenging task for modern computational fluid dynamics, mostly because of the tuning effort required for the sub-models used in the various frameworks (the Reynolds-averaged Navier–Stokes and large eddy simulation). Tuning is required b...

This paper analyzes the effect of antioxidants on engine combustion performance of a multi-cylinder diesel engine fueled with rubber seed biodiesel blends. Four antioxidants, namely 2-tert-butylbenzene-1,4-diol, N,N′-diphenyl-1,4-phenylenediamine, 2(3)-tert-Butyl-4-methoxyphenol and N-phenyl-1,4-phenylenediamine, were added at concentrations of 100...

The study of flame commencement and growth in SI engine has attracted the attention of many researchers due to its strong dependence to the in-cylinder flow and its capability to influence flame propagation characteristics in SI engines. Optical visualisation has been one of the prominent techniques utilized in this study of the early flame propert...

A new simple model for the puffing/micro-explosion of water-fuel emulsion droplets is suggested. The model is based on the assumption that a spherical water sub-droplet is located in the centre of a larger fuel droplet. The fuel is approximated by n-dodecane. The fuel droplet surface temperature is assumed to be fixed, and fuel evaporation is ignor...

Intake generated flows are known to have a fundamental influence on the combustion both in spark ignition (SI) and compression ignition engines. This study experimentally investigated the tumble flow structures inside a cylinder of gasoline direct injection (GDI) engine utilizing a stereoscopic time-resolved particle image velocimetry (PIV). The ex...

Recently, proper orthogonal decomposition (POD) technique has gained wide attractiveness as a powerful analysis tool in engine flows. The velocity vector fields resulted from high speed time-resolved particle image velocimetry (PIV) of the flow field inside an engine cylinder under steady-state conditions were investigated by proper orthogonal deco...

Water-in-diesel emulsions are known to lead to micro-explosions when exposed to high temperatures, thereby offering a technology that could improve the mixing of fuels with the ambient gas. Several factors such as the surfactant type, dispersed water droplet size, water content and coalescence rate play a key role in the onset of micro-explosion oc...

This paper studies the effect of intake manifold in order to obtain minimum turbulence and lower pressure drop. The pressure input was 1.2 bar where the effect is equal to turbocharge concept in conventional engine due to the stroke length. The experiment has been conducted in order to validate the method of theory with experimental PIV and CFD sim...

Free piston engine generator (FPEG) in the engine system can be considered as a linear energy conversion system. Cascade control for the stability of piston operation level and PID controllers are proposed for both the outer and inner loop. The free movement of the piston in the cylinder an adjust the compression ratio and optimize the combustion p...

The free piston linear generator (FPLG) is a kind of linear free-piston engine and has many advantages over the conventional internal combustion engine. In this study, a novel two-stroke free piston linear generator prototype equipped with a linear electric generator is presented to achieve efficient conversion of mechanical work to electricity dur...

Water-in-diesel emulsions are known to lead to micro-explosions when exposed to high temperatures, thereby offering a technology that could improve the mixing of fuels with the ambient gas. Several factors such as the surfactant type, dispersed water droplet size, water content and coalescence rate play a key role in the onset of micro-explosion oc...

In this paper, the bouncing phenomena of Free Piston Linear Generator (FPLG) and its influence on dynamic and combustion performance of FPLG during the starting process have been investigated. Using Simulink, FPLG was simulated by injecting compressed air at the combustion chamber and the piston was allowed to expand until bouncing phenomena occurr...

Increasing concern on the environment and energy security boosts the technological development of internal combustion engine with the main objectives are higher overall efficiencies and lower emissions. Split cycle engine is one of the unconventional solution for the current established engine technology. However, its high pressure ratio intake bet...

The present work analyzes the effect of antioxidants on engine combustion performance of a multi-cylinder diesel engine fueled with PB30 and PB50 (30 and 50 vol.% palm biodiesel (PB)). Four antioxidants namely N,N'-diphenyl-1,4-phenylenediamine (DPPD), N-phenyl-1,4-phenylenediamine (NPPD), 2(3)-tert-Butyl-4-methoxyphenol (BHA), and 2-tert-butylbenz...

Water-in-diesel emulsions potentially favor the occurrence of micro-explosions when exposed to elevated temperatures, thereby improving the mixing of fuels with the ambient gas. The distributions and sizes of both spray and dispersed water droplets have a significant effect on puffing and micro-explosion behavior. Although the injection pressure is...

Proper orthogonal decomposition (POD) is a coherent structure identification technique based on either measured or computed data sets. Recently, POD has been adopted for the analysis of the in-cylinder flows inside internal combustion engines. In this study, stereoscopic particle image velocimetry (Stereo-PIV) measurements were carried out at the c...

An integrated Design of Experiments (DoE) with Reynolds Averaged Navier Stokes (RANS) approach is suggested and implemented to model turbulent spray combustion. In the automotive industry, DoE is often combined with an optimizer and is used to find an optimum set of internal combustion engine calibration parameters for set criteria at reduced exper...

This paper describes an experimental study aimed at the characterization of the steady-state tumble motion in the cylinder of an engine using stereoscopic particle image velocimetry (Stereo-PIV). More specifically, a pent-roof four valves gasoline direct injection (GDI) engine head was mounted on a modified FEV steady-state flow rig for applying St...

Study on the behavior of Free Piston Linear Generator (FPLG) motion using gas spring. The potential energy from the bouncing behavior can be used to control the compression pressure of FPLG as well as improve the combustion process

The number and size distributions of the water dispersed phase have a significant effect on both the long-term stability of an emulsion, and the probability of micro-explosions inside an engine. The emulsions are subjected to intense pressure and shear flow in the fuel injection equipment resulting in changes in the number and size distributions of...

In consideration of its vast resources in Malaysia, the potential use of a nonedible biodiesel source from rubber seed oil (RSO) is explored. However, a mixture with a high saturation content feedstock is required to increase its oxidation stability, which is caused by its 78.93% unsaturation content. Two blends of 20% and 50% v/v rubber seed biodi...

A transient axially symmetric two-phase vortex-ring flow is investigated using the one-way coupled, two-fluid approach. The carrier phase parameters are calculated using the approximate analytical solution suggested by Kaplanski and Rudi (Phys. Fluids vol. 17 (2005) 087101–087107). Due to the vortical nature of the flow, the mixing of inertial admi...

This paper experimentally investigates the effect of boost pressure on the in-cylinder flow field under steadystate conditions using stereoscopic particle image velocimetry (Stereo-PIV) through increasing the pressure difference across the intake valves. The FEV steady-state flow bench was modified to provide an optical access into the cylinder reg...

This paper experimentally investigates the effect of boost pressure on the in-cylinder flow field under steady-state conditions using stereoscopic particle image velocimetry (Stereo-PIV) through increasing the pressure difference across the intake valves. The FEV steady-state flow bench was modified to provide an optical access into the cylinder re...

The use of a clean fuel such as biodiesel has both environmental and economic advantages. The environmental advantage is reduced emissions, whereas the economic benefit stems from local availability of raw material and improved energy security. Currently most of biodiesel production comes from edible sources such as soybean, palm and sunflower oils...

Emission Standards are usually targeted at protecting human health and the environment by certifying that automotive experts build engines that guarantee acceptable air quality. For automotive experts, this task must be accomplished without forfeiting power and performance intended for end-users of automobiles. In this light, a survey was conducted...

A b s t r a c t A transient axially symmetric two-phase vortex-ring flow is investigated using the one-way coupled, two-fluid approach. The carrier phase parameters are calculated using the ap- proximate analytical solution suggested by Kaplanski and Rudi (Phys. Fluids vol. 17 (2005) 087101–087107). Due to the vortical nature of the flow, the mixi...

Emulsion droplet size plays a key role in the micro-explosion occurrence as well as the stability of the emulsion. In a high-pressure common rail system, the water-in-diesel emulsion is subjected to intense pressure, temperature and shear when passing through the common rail and injector nozzle thereby altering the droplet size distributions as wel...

The current study demonstrates an experimental investigation of the tumble flow structures using Particle Image Velocimetry (PIV) under steady-state conditions considering the central vertical tumble plane. The experiments were carried out on a four-valve, pent-roof Gasoline Direct Injection (GDI) engine head at different valve lifts and with a pre...

Combustion phasing is the main obstacle to the development of controlled auto-ignition based (CAI) engines to achieve low emissions and low fuel consumption operation. Fuel combinations with substantial differences in reactivity, such as diesel/compressed natural gas (CNG), show desirable combustion outputs and demonstrate great possibility in cont...

Better performance and higher efficiency of the vehicles can be achieved by using free piston engine, in which the piston is connected directly to the linear generator and waiving of any mechanical means. The free piston engine has the ability to overcome or reduce many of the challenges, such as the carbon dioxide (CO2) emission and fossil fuel co...

Designing future ultra-high efficiency, ultra-low emission engines requires an in depth understanding of the multi- scale, multi-phase phenomena taking place in the combustion chamber. The performance of the fuel delivery system is key in the air fuel mixture formation and hence the combustion characteristics, however in most spray modelling approa...

The Direct Numerical Simulation (DNS) approach to solving the fundamental transport equations down to the smallest scales of motion is favorable should the requirement be a truly predictive solution of fluid dynamic problems, but the simulation run times are unacceptable for most practical industrial applications. Despite the steadily increasing co...

The conventional Diesel cycles engine is now approaching the practical limits of efficiency. The recuperated split cycle engine is an alternative cycle with the potential to achieve higher efficiencies than could be achieved using a conventional engine cycle. In a split cycle engine, the compression and combustion strokes are performed in separate...

In-cylinder air flow structures are known to strongly impact on the performance and combustion of internal combustion engines (ICE). Therefore the aim of this paper is to experimentally study an IC engine in-cylinder flow under steady-state conditions. Different methods can be used to characterize the in-cylinder flow which are optical engines and...

Alternatives to hydraulic drives that used on vehicles are necessary in order to reduce the Carbon dioxide (CO2) emission and oil consumption. Hence better performance and efficiency of the vehicles can be achieved by using free piston engine, in which the piston reciprocate linearly with a permanent magnet linear generator (PMLG) without the need...

An experimental study was conducted to investigate the effect of the structure of the induction flow on the characteristics of early flames in a lean-stratified and lean-homogeneous charge combustion of compressed natural gas (CNG) fuel in a direct injection (DI) engine at different engine speeds. The engine speed was varied at 1500 rpm, 1800 rpm a...

Most of the currently used models for droplet heating and evaporation are based on the assumption that droplets are perfect spheres. At the same time the shapes of many observed droplets in engineering applications are far from spherical. We have studied the influence of droplet non-sphericity on their heating and evaporation, approximating droplet...

The microexplosion evolution phenomenon of single droplets of water in pure diesel emulsion under Leidenfrost effect has been studied. The tested emulsions were stabilized with a blend of commercial surfactants with three different water contents of 9%, 12%, and 15%. A high speed camera synchronized with backlight technique was used to capture the...

Background and Objective: Using Natural gas (NG) for combustion process modification in compression ignition engines is considered to be a promising method due to its high volumetric efficiency, high thermal efficiency and low emissions. However, the Natural gas has a penalty in terms of how to be involved in a combustion process due its high auto-...

In this study, the potential of using non-edible biodiesel source (rubber seed oil) was explored. Rubber seed oil (RSO) is a promising non-edible source for producing a sustainable biodiesel in Malaysia. However, due to the lower oxidation stability of the produced biodiesel which is the result of its higher unsaturation content (78.73%), an oxidat...

Emissions from diesel engines have been considered as major air pollution sources. The blending of feedstocks is motivated by the desire to enhance the properties and reduce the cost of biofuels. In this study, a rubber seed/palm oil mixture at equal blend ratios was used to produce biodiesel. The effects of irreverent parameters on transesterifica...

The fully Lagrangian approach (FLA) to the calculation of teh number density of inertial partucles in dilute gas-particles flows was incorporated into teh CFD code ANSYS Flunet. The new verion of ANSYS Fluent was applied to moedling dilute gas-particle flow around a cylinder and liquid droplets in a gasoline fuel spray. In a steady-state case, thre...

Generating power is of great importance nowadays across the world. However, recently, the world became aware of the climatic changes due to the greenhouse effect caused by CO2 emissions and began seeking solutions to reduce the negative impact on the environment. Besides, the exhaustion of fossil fuels and their environmental impact, make it is cru...

Two phase liquid-gas slug flow is a source of vibration and fatigue on pipe walls and downstream equipment. This paper examines the effect of inlet conditions on the stream-wise velocity profiles and on the shear stresses induced by the liquid phase on the pipe wall during the slug flow. Instantaneous velocity vector fields of the liquid-gas (water...

In a series of our earlier papers, basic properties of vortex ring-like structures in gasoline engines were interpreted in terms of the generalised vortex ring model. In the present paper, a model that can be regarded as a unified theoretical framework for modelling of conventional vortex rings, confined vortex rings and confined vortex rings with...

The microexplosion evolution phenomenon of single droplets of water in pure diesel emulsion under Leidenfrost effect has been studied. The tested emulsions were stabilized with a blend of commercial surfactants with three different water contents of 9%, 12% and 15%. A high speed camera synchronized with backlight technique was used to capture the e...

A novel intra-cycle waste heat recovery (ICWHR) methodology, applied to an internal combustion engine is presented in this study. Through a split type thermodynamic cycle design, quasi-isothermal compression of the charge air and isobaric combustion of the air/fuel mixture can be performed separately in two chambers. Within such a design, the exhau...

To predict the performance of a fluidized bed gasifier (FBG) using date palm seeds (DPSs) as feedstock, a two-phase model was developed. The model simulates the hydrodynamic, kinetic reaction and steady state operations using the Aspen plus software. Experimental works were performed to study the effect of bed temperature, steam to biomass ratio, g...

Waste heat recovery is a key path in improving the overall thermal efficiency, and hence, reducing CO2 emissions in the mid to large scale internal combustion engines. However, realisation of the cost-effective deployment of Organic Rankine Cycles (ORC) are hindered by several key factors. Amongst these are the, utilisation of low-grade ORC practic...

The main ideas of the model for droplet heating and evaporation, based on the analytical solution to the heat conduction equation inside the droplet, and its implementation into ANSYS Fluent are described. The model is implemented into ANSYS Fluent using User-Defined Functions (UDF). The predictions of ANSYS Fluent with the new model are verified a...

The split cycle engine is a new reciprocating internal combustion engine with a potential of a radical efficiency improvement. In this engine, the compression and combustion–expansion processes occur in different cylinders. In the compression cylinder, the charge air is compressed through a quasi-isothermal process by direct cooling of the air. The...

The effects of engine speed and load, and fuel blend ratio on the emissions and performance of an IDI (indirect injection) diesel engine were investigated. A 50:50 vol. blend of rubber seed and palm oils was used for the biodiesel production to reduce costs and enhance properties. Oil acid was reduced from 33.4 to 1.42 mg KOH/g oil by esterificatio...

Emulsified fuels considered as a promising alternative fuel that could solve and meet the increasingly stringent emission regulations for diesel engines due to their capability of reduction the harmful exhaust emission, such as carbon monoxide (CO), nitrogen oxides (NOx) and particulate matter (PM). The admission of water into the diesel fuel has s...

The stringent emission regulations and the need to increase fuel efficiency makes controlled auto-ignition (CAI) based combustion an attractive alternative solution to these issues. However, the combustion control is the main obstacle to its development. Fuel combinations with substantial different in reactivity such as diesel/compressed natural ga...

Road transport is a key source of ambient pollution especially in urban regions. While the moderation of engine-out emissions from road transport is seen as key in the improvement of global air quality, the overall sales of automobiles which contribute to air pollution keep rising. This trend has impelled global alertness due to the grave consequen...

This study investigated the impact of fumigating different percentages of anhydrous ethanol (E) and cetane number enhancer (CNE) on the combustion, performance as well as exhaust pollutants of DI diesel engine. The addition of this mixture (ECNE) exhibited higher premixed combustion peaks, faster combustion process, and higher coefficient of variat...

The stringent emissions and needs to increase fuel efficiency makes controlled auto-ignition (CAI) based combustion an attractive alternative for the new combustion system. However, the combustion control is the main obstacles in its development. Reactivity controlled compression ignition (RCCI) that employs two fuels with significantly different i...

The Proper orthogonal decomposition (POD) method has seen increasingly used in the last two decades and has a lot of applications for the comparison of experimental and numerically simulated data. The POD technique is often used to extract information about coherent structures dominating the flow. The two-dimensional and two-component instantaneous...

Using particle imaging velocimetry (PIV), we observed particle motion within the stable operating regime of a swirling fluidized bed with an annular blade distributor. This paper presents velocity profiles of particle flow in an effort to determine effects from blade angle, particle size and shape and bed weight on characteristics of a swirling flu...

A meshless method for modelling two-phase flows with phase transition is described. The method is based on consideration of three systems: viscous-vortex blobs, thermal-blobs and droplets; and can be applied for numerical simulation of 2D non-isothermal flows of ‘gas-evaporating droplets’ in the framework of the one-way coupled two-fluid approach....

The paper presents an overview of recent progress in the modelling of vortex rings and vortex ring-like structures with specific potential applications to direct injection gasoline engines. A new theoretical model for a confined axisymmetric vortex ring is described. The predictions of this model are shown to be in agreement with available experime...

The application of the discrete component model for heating and evaporation to multi-component biodiesel fuel droplets in direct injection internal combustion engines is described. This model takes into account the effects of temperature gradient, recirculation and species diffusion inside droplets. A distinctive feature of the model used in the an...

Due to increasing CO2 emissions and fuel costs there is a growing interest in heat to power conversion techniques for Heavy Duty Diesel Engines (HDDE). The use of Rankine Cycle (RC) and Organic Rankine Cycles (ORC) on long-haul HDDE is seen as a possible way to improve the overall system efficiency. The key consideration in the research and develop...

This paper examines the effect of gas and liquid superficial velocities on the dynamics of the slug flow in anearly horizontal pipeline. Instead of the invasive measurements the experiments were conducted usingnon-invasive techniques to measure slug frequency and bubble length in the slug flows. A simultaneous PIV-LIFtechnique was employed to measu...

The current experimental ORC setups for long-haul Heavy Duty Diesel Engines (HDDE) are not reaching the desired fuel savings within the expected costs. Pathways to improve ORC performance and cost-effectiveness remain a major challenge facing the automotive sector. This paper presents the conceptual overview and simulation results (using Aspen HYSY...

The analysis of a two-phase slug flow is of immense importance due to its vast applications in many industrial problems. A number of experimental and analytical studies have been carried out to study this complex and unwanted phenomenon. Mostly, these studies were limited to the liquid phase and to the statistical parameters and formation mechanism...

The temporal and spatial structures of turbulent liquid phase (water) in pipelines were investigated. Two cases were considered one single liquid phase flow at 80 l/m, second slugy part of slug flow by introducing gas (compressed air) at 60 l/m while keeping liquid flow rate same. Particle image velocimetry (PIV) was used for quantitative measureme...

Detailed measurements of near-nozzle spray formation are essential to better understand and predict the physical processes involved in diesel fuel atomisation. We used long-range microscopy to investigate the primary atomisation of diesel, biodiesel and kerosene fuels in the near-nozzle region, both at atmospheric and realistic engine conditions. H...