Top PDF An experimental investigation of flame spreading from bluff body flameholders

An experimental investigation of flame spreading from bluff body flameholders

An experimental investigation of flame spreading from bluff body flameholders

- 10ax, PRWEDIURE AND BPSLBiM3tNABY EXPERIMENTS proc&ure, jfn this investigation, spark ScMisrc~snphotsgrapks were used to determine the width sf tbs burnt gagi wake, a typical Schlieren[r]

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Experimental and numerical investigation of a double concentric bluff body flameholder

Experimental and numerical investigation of a double concentric bluff body flameholder

1 Model Outline for Single Bluff Body 23 4.2 24 Boundary Conditions for Single Bluff Body 4.3 Grid Structure for Single Bluff Body 25 4.4 Model Outline for Double Bluff Body 4.5 Boundary[r]

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An experimental investigation of flow conditions behind a bluff body flameholder

An experimental investigation of flow conditions behind a bluff body flameholder

totnl comhstion efficiency wag determined by multiplying t:%e local co~2buarjo32 affidalzcy by $he corresponang Pocg3 maan Bow rate ra-... Pnvesagaaon of t.he CO conc[r]

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Acceleration of Bluff Body Calculation Using Mdgrape-2

Acceleration of Bluff Body Calculation Using Mdgrape-2

There are two techniques to reduce the force calculation cost of an N-body simulation: hardware and software techniques. In the hardware, there are two techniques, one is a parallel computer and the other is a special-purpose computer. To accelerate the vortex methods calculation, parallel computation has been widely used in previous studies [9;11-14]. Even though accelerate the calculation significantly; there are some difficulties to use parallel computations for longer calculations. It has limitations with parallelization according to hardware specifications. The memory bandwidth is a big problem to calculate for large number of vortex elements, which required special consideration. Power consumption and heat dissipation interrupt the longer time calculations. These problems are becoming serious for advanced scientific computation. Shortcomings of parallel computers, the special-purpose approach can solve parallelization limit thoroughly. It has relaxed power consumption according to hardware specification.
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Investigation of Turbulent Lifted Jet Flame Stabilization using Experimental Methods and Simulations.

Investigation of Turbulent Lifted Jet Flame Stabilization using Experimental Methods and Simulations.

50 chemiluminescence images and raw PIV data to determine the flame position and flame edges. As opposed to previous studies, which tend to examine velocities upstream of the reaction zone, the present study focuses on velocities crossing into the high temperature zone. In this approach, the velocity field in the vicinity of the upstream portion of the reaction zone is examined in detail, along with flow behavior in the surrounding regions. Given the state of the field, these velocity fields are examined for elements that support the existence of premixed branches (i.e., flow steering across (partial) anchor-shaped reaction zones). The velocities found are compared to the laminar averaged premixed flame speeds and the variation of the velocities through the reaction zone is investigated. While studies of reactive scalars at the leading edge yield unclear results as to the morphology of the various flame branches, the details of the velocity jumps inside the high temperature zone are quite consistent with those of a partially premixed flame region. Thus, a contribution of this paper is in the area of supporting partially premixed combustion through velocity field data, rather than through arguments based on reactive-scalar field data.
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Limit Cycle Characterization of an Aeroelastic Wing in a Bluff Body Wake.

Limit Cycle Characterization of an Aeroelastic Wing in a Bluff Body Wake.

When the bluff body is moved to X b /D = 5.6 (Fig. 4.10(b)), f shed − 3 f LCO is still present in the envelope CWT, however it is no longer the only modulation frequency. In this case, the LCO response alternates between two modulation modes, represented by the two dominant modula- tion frequencies seen in the envelope CWT. Further evidence of this is provided by Fig. 4.10(c) in which X b /D = 4.3 and the two modes are even more pronounced. Among the two distinct modulation modes present, the first is a low frequency mode that persists during the first 60 seconds of the trial and causes a relatively intense modulation of the LCO amplitude. The sec- ond is a higher frequency mode representing f shed − 3 f LCO which dominates between t = 80 sec. and t = 120 sec. and produces a less intense modulation. Figure 4.10(c) also shows tran- sient period between the two modes (t = 60 sec. to t = 80 sec.) in which neither frequency dominates entirely.
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Simulation of vortex induced vibration of a bluff body structure

Simulation of vortex induced vibration of a bluff body structure

The computational method is used to analyse a bluff body responses when exposed into specific fluid flow condition. A model is developed using Fluent 15, an application tools for fluid dynamics analysis from ANSYS Inc, whilst the principle data and flow condition is taken from numerical simulation. Both results will be compared to find dissimilarities as many discrepancies occur between measurements and predictions from empirically based codes and CFD is always reported (Song et al., 2011).

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Effects of Inlet Parameters on the Performance of Bluff Body Combustion

Effects of Inlet Parameters on the Performance of Bluff Body Combustion

Ground-based or aero gas turbine applications incorporate flame holders in the form of bluff bodies or swirlers for a primary or secondary combustion in high speed reacting flows. These two methods are very prominent among combustion systems over a long time. Recent gas turbine combustors use a combination of the two for a more efficient combustion process. Researchers have been studying the effects of fluid flow inside a combustion chamber which is characterized by high turbulence caused by the wake formation.

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Simulation of rear surface contamination for a simple bluff body

Simulation of rear surface contamination for a simple bluff body

Clearly this experimental system is highly simpli fi ed: wheels have been omitted and the spray is introduced centrally, rather than at outboard positions, as would be the case if tyre interaction with a wet road were responsible for the spray. Neither have particle velocities been matched to those seen for droplets released from tyre surfaces. However, it does allow for the investigation of the basic process of spray transport into the base wake and the deposition of material on the rear surface given its presence in the wake. The following section presents and discusses the results obtained. As a physically realistic aerodynamics simulation is a prerequisite for a credible simulation of surface contamination accumulation, these results are discussed fi rst.
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Investigation of Biogas Moderate or Intense Low Oxygen Dilution (MILD) combustion on open furnace bluff-body burner

Investigation of Biogas Moderate or Intense Low Oxygen Dilution (MILD) combustion on open furnace bluff-body burner

Furnace: 1000°C and 650°C air preheat temperature, - No flame could be seen, Fuel was completely burnt, CO was below 1ppm in the exhaust Called that condition “flameless oxidation” or FL[r]

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The evolution of edge vortices underneath a diffuser equipped bluff body

The evolution of edge vortices underneath a diffuser equipped bluff body

The PIV surveys at various streamwise locations indicate that the edge vortex evolves from a weak region of recirculation attached to the diffuser ramp, into a strong detached concentrated vortex. Near the inlet of the diffuser the physical space between the diffuser ramp and the ground plane is small constraining the swirl of the flow and hence limiting the size and strength of the recirculation region. As the distance between the diffuser ramp and the ground plane increases, i.e. an increase in streamwise location, the flow is less constrained and can therefore generate a vortex detached from the model. The PIV surveys in figure 5 indicate that the vortex does not undergo breakdown since the streamwise pressure gradient is not adverse enough. However it has been shown that reducing the ride height causes the vortex to breakdown (fig. 4). It could therefore be hypothesized that reducing the ride height would alter the evolution of the vortex in such a way as to promote breakdown prior to the exit of the diffuser.
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The Optimization Of Pressure Different Rear Suction Airflow Correction Device Based On The Ratio Inlet Over Outlet In Motivation Of Aerodynamic Drag Reduction

The Optimization Of Pressure Different Rear Suction Airflow Correction Device Based On The Ratio Inlet Over Outlet In Motivation Of Aerodynamic Drag Reduction

Sir George Cayley in 1979 invented a vehicle that able to travel in the aerospace. Four elements of aerodynamic has been used in order to make the device fly which are lift, thrust, drag and weight. The device was basically a glider and it contains 2 wings and flap and also it was made from wood to carry one people at one time. (Ackroyd 2011). The Wright brother further the design from Sir George Cayley and invented the first ever engine powered aircraft in 1903. Helicopter was also invented after further development on the aircraft has been made. Bernoulli principle was used in helicopter main rotor as the thrust was gained to produce lift force. Ludwig Prandtl stated that pressure distribution over surface body is changed once the flow separates. Pressure drag was created due to unbalanced force that act in multiple direction. (Jr 2005). The design on the aircraft structure require information on external load that are being applied to the individual external parts of the aircraft. The flight dynamics of the aircraft analysis calculates aerodynamic loads exerting on the cockpits, fuselage and wings and after further analysis is conducted to predict structural response for example deformation, stress distributions and vibrations (Wang 2016).
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INFLUENCE OF AFTER BODY SHAPE ANGLE OF TRAPEZOIDAL BLUFF BODY ON MEASURED SIGNAL PARAMETERS

INFLUENCE OF AFTER BODY SHAPE ANGLE OF TRAPEZOIDAL BLUFF BODY ON MEASURED SIGNAL PARAMETERS

The Strouhal’s number increases with the after body shape angle. The increase in Strouhal’s number is higher for the 19° angle for all blockage ratios. It is more than 22° in some cases. As Strouhal’s number is directly proportional to vortex frequency, we can say that vortex frequency is strong and higher with 19° after body shape angle. The vortex frequency increases as the shear layer velocity increases because of the local increase in flow speed around bluff body with increase in blockage ratio. The increase in vortex frequency is also affected by after body shape. In visualization experiments it is observed that, the increase in after body angle reduces the wake width. The wake width is inversely proportional to the vortex frequency.
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Experimental investigation of the adsorption of Rhodamine-B from aqueous solution onto activated carbon from water hyacinth

Experimental investigation of the adsorption of Rhodamine-B from aqueous solution onto activated carbon from water hyacinth

For continuous-flow adsorption studies, a column of 9 cm diameter and 35 cm length was used. The column was packed with the dried and weighed adsorbent. From the standard stock solution, 100 mg of dye was dissolved in 100 ml of distilled water to make 1 ml of Rhodamine-B equivalent to 1 mg. Then suitable concentrations of Rhodamine-B were prepared for the studies and taken in the column and the unadsorbed Rhodamine-B was collected from the outlet at a constant rate. The concentration of the residual dye was analyzed spectrophotometrically.

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An Experimental Investigation on Treatment of Tannery Effluent Using Azadirachta Indica

An Experimental Investigation on Treatment of Tannery Effluent Using Azadirachta Indica

Indian leather industry has established to a large range and is the second larger producer following to China. The industry is equipped mostly with a potential for employment generation, growth and exports, with the annual export touching 2 billion USD. Presently it is on an ever increasing phase with optimum utilization of available raw materials and returns from exports.

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An Experimental Investigation of ZnO Nanoparticles Effect on the Acrylic Coatings

An Experimental Investigation of ZnO Nanoparticles Effect on the Acrylic Coatings

C 3 H 6 O all were purchased from Merck company and were used in this research without any purification. paraloid resin B72, dual (binary) copolymer from Methyl Acrylate (MA) and Ethyl Methacrylate (EMA) with approximate molar ratio of 5:2 were purchased from Lascaux Restauro company. Steel sheet Ck60 was used as sublayer. This sheet was cut into smaller pieces with dimensions of 36 cm 2 . In order to obtain

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Influence of diffuser angle on a bluff body in ground effect

Influence of diffuser angle on a bluff body in ground effect

A symmetrical body in ground effect will generate aerodynamic force pointed to the ground 共 downforce 兲 . The flow between the body and the ground is accelerated leading to reduced pressure. Introducing camber to the body in the form of an upswept ramp at the rear creates a diffuser between the ground and the body. Since the diffuser exits to the base pressure of the model, the flow under the model accelerates to a greater degree than without the diffuser. This increase in downforce is accompanied by complex flow physics within the diffuser. The upsweep initiates three- dimensional flow separation which leads to vortex formation and possible flow reversal. This area of research is especially impor- tant in the automobile industry with respect to performance and safety. A complete understanding of the complex fluid flow phys- ics is essential for the development of flow control measures.
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Experimental Investigation on Effect of Chemical Composition on Stability of Flame

Experimental Investigation on Effect of Chemical Composition on Stability of Flame

8. S.P. Marshall, et al studied the laminar burning velocity measurements of liquid fuels at elevated pressures and temperatures with combustion residuals. They used the method of a “Constant volume vessel” (rated at 3.4 MPa) in conjunction with a multi-zone model to calculate burning velocity from pressure and schlieren data, allowing the user to select data uncorrupted by heat transfer or cellularity. n-Heptane, iso-octane, toluene, methyl benzene and ethanol were tested over a wide range of initial pressures (50,100,200and400kPa), temperatures (310,380and450K) and equivalence ratios (0.7–1.4), along with tests using combustion residuals at mole fractions of up to 0.3.
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Experimental Studies on Bluff Bodies

Experimental Studies on Bluff Bodies

ABSTRACT: This paper presents the experimental studies on Bluff bodies. In the present study a blunt nosed body with and without spike having the L/W =1 and 1.5 , where W is the width of the model and L is the length of the spike are chosen. The zone of influence and the positive pressure field over the nose for a blunt-nosed body, with and without spike were measured by direct means. Flow past the body, with and without spikes was visualized in a two dimensional water channel at a Reynolds number 6620. It is found that the spike reduces the radius of curvature of the approaching streamline, and the deflection of the streamline is towards the shoulder of the basic body resulting in a narrow zone of positive pressure hill at the nose. The spike with hemispherical nose reduces the zone of influence.
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