This paper is devoted to study the effect of crashing of vehicles with concrete blocks that placed around lighting poles. Unexpected dangers takes place if crashing occurs. It may cause death of the driver and passengers, or severe injuries. In order to minimize or eliminate this risk, a system made of corrugated composite material plates have been designed to replace the concrete blocks around lighting poles. This system is made of reinforced fiber glass and it is modeled to crash with a model of car exactly similar to the real one, forming a simulation of car accident. Modeling process takes place using Finite Element Analysis (FEA). ANSYS software utilized for this purpose. Simulation was performed at three different speeds of the vehicle. Results obtained have been recorded in a form of deformed mesh, and contours. The results proved that the new designed system is working perfectly and it has the ability to absorb impact energy caused by car accident. Therefore, by using composite material instead of concrete, risk of death and injuries will minimized or completely eliminated.

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ABSTRACT

Swirl stabilised combustion is one of the most widely used techniques for flame stabilisation in gas turbine combustors. Lean premixed combustion systems allow the reduction of NOx coupled with fair flame stability. The swirl mechanism produces an aerodynamic region known as central recirculation zone (CRZ) providing a low velocity region where the flame speed matches the flow velocity, thus anchoring the flame whilst serving to recycle heat and active chemical species to the root of the f

ormer. Another beneficial feature of the CRZ is the enhancement of the mixing in and around this region. However, the mixing and stabilisation processes inside of this zone have shown to be extremely complex. The level of swirl, burner outlet configuration and combustor expansion are very important variables that define the features of the CRZ.

Therefore, in this paper swirling flame dynamics are investigated using computational fluid dynamics (CFD) with commercial software (ANSYS). A new generic swirl burner operated under lean-premixed conditions was modelled. A variety of nozzles were analysed using several gaseous blends at a constant power output. The investigation was based on recognising the size and strength of the central recirculation zones. The dimensions and turbulence of the Central Recirculation Zone were measured and correlated to previous experiments. The results show how the strength and size of the recirculation zone are highly influenced by the blend and infer that it is governed by both the shear layer surrounding the Central Recirculation Zones (CRZ) and the gas composition

The main objective of this paper is to study the effect of replacing

the internal casing of water boiler that made of metallic material by a

similar one made of composite materials. An intensive theoretical study

have been carried out on domestic electrical water boiler using modeling

technique. Analysis and modeling process was performed using Finite

Element Method. Thermal conductivity which is the main parameter

affecting heat transfer has been tested for composite material as well as

for metallic materials. Results showed that it is more convenient to use

composite material for inner case of water boiler instead of metallic

material. Composite materials are lighter than metallic material, much

safer (eliminate possibility of electrical shock), and it hasn't corrosion

problems. It is found that it is possible to replace the internal case of

water boiler made of metallic material with a wall thickness of 7 mm by

an equivalent composite material case made of glass fiber with the same

thickness. Obtained results showed that seven layers of composite

materials forming similar wall thickness is an optimum case with respect

of heat transfer and thermal conductivity.

A B S T R A C T

Swirl stabilised combustion is one of the most successful technologies for flame stabilisation in gas turbine combustors. Lean premixed combustion systems allow the reduction of NOx coupled with fair flame stability. The swirl mechanism produces an aerodynamic region known as central recirculation zone (CRZ) providing a low velocity

region where the flame speed matches the flow velocity, thus anchoring the flame whilst serving to recycle heat and active chemical species to the root of the former. Another beneficial feature of the CRZ is the enhancement of the mixing in and around this region. However, the mixing and stabilisation processes inside of this zone have shown to be extremely complex. The level of swirl, burner outlet configuration and combustor expansion are very important variables that define the features of the CRZ. The complex fluid dynamics and lean conditions pose a problem for stabilization of the flame. The

problem is even more acute when alternative fuels are used for flexible operation.

Therefore, in this paper swirling flame dynamics are investigated using computational fluid dynamics (CFD) with commercial software (ANSYS). A new generic swirl burner operated under lean-premixed conditions was modelled. A variety of nozzles were analysed using isothermal case to recognize the the behavers of swirl.

The investigation was based on recognising the size and strength of the central recirculation zones. The dimensions and turbulence of the Central Recirculation Zone were measured and correlated to previous experiments. The results show how the strength and size of the recirculation zone are highly influenced by both the shear layer surrounding the Central

Recirculation Zones (CRZ) and outlet configurations.

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Abstract—Solar water heaters are used widely in places where solar energy is abundant. However, thermal energy storage systems are required due to the availability of solar energy only during day-time. The solution to this need is to design a thermal storage system with PCMs to provide hot water for domestic usage during night-time. This paper aims to provide a numerical simulation of the storage tank using ANSYS software, in which phase change materials are being utilized to find alternative ways to improve the thermal efficiency of hot water tanks. The factors that increase this efficiency, such as improving the thermal conductivity of paraffin wax using Encapsulated Phase Change Materials (PCMs) as spheres around the heat exchanger and the time for melting and solidification will be studied

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Abstract

Lean premixed swirl stabilized combustion is one of the most successful technologies for NOx reduction in gas turbines. The creation of inherent coherent structures such as recirculation zones is one of the main advantages of these flow-stabilized systems since these zones create regions of low velocity that allow heat transfer improvement between reactants and products while increasing residence time for unburned species. However, these effects can also affect the stability of the flame under lean conditions, with various instabilities that can appear during the combustion stage such as flashback, blowoff, autoignition, etc. These processes are even more complex when new alternative fuels are being used for power generation applications. Synthesis gases (syngas) are some of the most concerning out of the available range of fuels as their heating values, flame speeds, ignition energies, etc. are highly dependent on the combination of species that comprise them. Since new gas turbines need to deal with these new blends for fuel flexibility and current lean premixed swirled stabilized systems seem to be the most cost effective-technical option to keep NOx down, gas turbine designers need more information on how to properly design their equipment to achieve stable flames with low NOx whilst avoiding instabilities.

Therefore, this paper presents a study using numerical and experimental analyses to provide guidance on the use of CH4/H2/CO blends in tangential swirl burners. Methane content was decreased from 50% to 10% (volume) with the remaining amount being split equally between carbon monoxide and hydrogen. Ambient temperature conditions were assessed using a swirl number close to 1.0. Particle Image Velocity was used to experimentally validate numerical predictions and determine features of the coherent structures affecting the flame close to the nozzle. Modelling was carried out employing the k-ω SST turbulence model, providing more information about the impact of these structures and the flame turbulent nature close to blowoff limits. The study emphasizes the analysis of various nozzles with different angles and how these geometrical changes at the outlet of the swirl chamber affect the onset of blowoff. Recommendations on the use of RANS CFD modelling are provided on the basis of blend composition.