Experimental Study on the Production of CO-NO-HC Emissions in the Radial Swirling Flow Combustion System

2014 ◽  
Vol 69 (2) ◽  
Author(s):  
Mohamad Shaiful Ashrul Ishak ◽  
Mohammad Nazri Mohd Jaafar
Keyword(s):  
Swirling Flow ◽  
Recirculation Region ◽  
Mixing Enhancement ◽  
Swirl Number ◽  
Swirl Angle ◽  
Low Emission ◽  
Air Mixing ◽  
Hc Emissions ◽  
Vane Angle ◽  
Fuel Burner

The main purpose of this paper is to evaluate the production of CO-NO-HC emissions while varying the swirl angle of curve vane radial swirler. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion inside a burner system. Four radial curve vane swirlers with 30o, 40o, 50o and 60o vane angle corresponding to swirl number of 0.366, 0.630, 0.978 and 1.427 respectively were used in this analysis to show the effect of vane angle on emission production at end of combustion chamber. Pollutant NO reduction of more than 10 percent was obtained for the swirl number of 1.427 compared to 0.366. CO emissions were reduced by 20 percent, 25 percent and 38 percent reduction in carbon monoxide (CO) emission for swirl number of 0.630, 0.978 and 1.427 compared to swirl number of 0.366 respectively. Meanwhile, there was a small decrease in unburned HC emissions when increasing the swirl number for the whole range of equivalence ratios.  Results show that the swirling action is augmented with the increase in the vane angle, which leads to better performance of CO-NO-HC emission production inside liquid fuel burner system.

Experimental Analysis on the Formation of CO-NO-HC in Swirling Flow Combustion Chamber

2015 ◽  
Vol 72 (4) ◽  
Author(s):  
Mohamad Shaiful Ashrul Ishak ◽  
Mohammad Nazri Mohd. Jaafar ◽  
Wan Zaidi Wan Omar
Keyword(s):  
Combustion Chamber ◽  
Swirling Flow ◽  
Swirl Flow ◽  
Recirculation Region ◽  
Mixing Rate ◽  
Swirl Angle ◽  
Low Emission ◽  
Air Mixing ◽  
Efficient Combustion ◽  
Hc Emissions

The main purpose of this paper is to evaluate the production of CO-NO-HC emissions while varying the swirl angle of curve vane radial swirler. Swirling flow generates central recirculation region (CRZ) which is necessary for flame stability and enhances fuel air mixing. Therefore designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion inside burner system. Four radial curved vane swirlers with 30o, 40o, 50o and 60o vane angles corresponding to swirl numbers of 0.366, 0.630, 0.978 and 1.427 respectively were used in this experiment to measure the vane angles effect on emission production in the combustion chamber. Emission measurements were conducted at 5 axial distances from the burner throat, and at 5 locations along the radius starting the central axis at each section. It was found that at the core near the throat, CO and HC concentrations are low due to high available O2 and high fuel mixing rate producing efficient combustion. This is due to the high shear region created the high swirl flow.

Numerical Analysis on the CO-NO Formation Production near Burner Throat in Swirling Flow Combustion System

2014 ◽  
Vol 69 (2) ◽  
Author(s):  
Mohamad Shaiful Ashrul Ishak ◽  
Mohammad Nazri Mohd Jaafar
Keyword(s):  
Swirling Flow ◽  
Reverse Flow ◽  
Flow Behavior ◽  
Recirculation Region ◽  
Mixing Enhancement ◽  
Ansys Fluent ◽  
Pressure Losses ◽  
No Formation ◽  
Swirl Angle ◽  
Air Mixing

The main purpose of this paper is to study the Computational Fluid Dynamics (CFD) prediction on CO-NO formation production inside the combustor close to burner throat while varying the swirl angle of the radial swirler. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore, designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. A liquid fuel burner system with different radial air swirler with 280 mm inside diameter combustor of 1000 mm length has been investigated. Analysis were carried out using four different radial air swirlers having 30°, 40°, 50° and 60° vane angles. The flow behavior was investigated numerically using CFD solver Ansys Fluent. This study has provided characteristic insight into the formation and production of CO and pollutant NO inside the combustion chamber. Results show that the swirling action is augmented with the increase in the swirl angle, which leads to increase in the center core reverse flow, therefore reducing the CO and pollutant NO formation. The outcome of this work will help in finding out the optimum swirling angle which will lead to less emission.  

Numerical Analysis of Effect of Preheat and Swirl of Inlet Air on Temperature Profile in Canister Burner

2015 ◽  
Vol 72 (4) ◽  
Author(s):  
Mohamad Shaiful Ashrul Ishak ◽  
Mohammad Nazri Mohd. Jaafar ◽  
Wan Zaidi Wan Omar
Keyword(s):  
Temperature Distribution ◽  
Temperature Profile ◽  
Hot Spot ◽  
Flow Behavior ◽  
Recirculation Region ◽  
Mixing Enhancement ◽  
Ansys Fluent ◽  
Pressure Losses ◽  
Swirl Angle ◽  
Air Mixing

The main purpose of this paper is to study the Computational Fluid Dynamics (CFD) prediction on temperature distribution inside the canister burner with inlet air pre-heating of 100K and 250K while varying the swirl angle of the radial swirler. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore, designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. A liquid fuel burner system with different radial air swirler with 280 mm inside diameter combustor of 1000 mm length has been investigated. Analysis were carried out using four different radial air swirlers having 30°, 40°, 50° and 60° vane angles. The flow behavior was investigated numerically using CFD solver Ansys Fluent. This study has provided characteristic insight into the distribution of temperature inside the combustion chamber. Results show that with the inlet air preheat before the combustion, the temperature distribution inside the canister would stabilize early into the chamber with higher swirl number (SN) compared without inlet air preheat. As for the inlet air preheat, the main effects are the resulting temperatures in the canister are higher, but there is a smaller hot-spot in the flame. This means that the temperature profile in the chamber is well distributed.

The Effect of Inlet Air Preheat on CO and NO Production in the Combustion of Diesel in Canister Burner

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
Mohamad Shaiful Ashrul Ishak ◽  
Mohammad Nazri Mohd Jaafar ◽  
Wan Zaidi Wan Omar
Keyword(s):  
Fuel Injection ◽  
Flow Behavior ◽  
Recirculation Region ◽  
Mixing Enhancement ◽  
No Production ◽  
Injection Point ◽  
Ansys Fluent ◽  
Pressure Losses ◽  
Swirl Angle ◽  
Air Mixing

The main purpose of this paper is to study the Computational Fluid Dynamics (CFD) prediction on the formation of carbon monoxide and oxide of nitrogen (CO-NO) inside the canister burner with inlet air pre-heating of 100 K and 250 K while varying the swirl angle of the radial swirler. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore, designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. A liquid fuel burner system with different radial air swirler with 280 mm inside diameter combustor of 1000 mm length was investigated. Analyses were carried out using four different radial air swirlers having 30°, 40°, 50° and 60° vane angles. The flow behavior was also investigated numerically using CFD solver Ansys Fluent. Overall results show that inlet air preheat quickens the completion of combustion such that the CO and NO production stabilized at a point nearer to fuel injection point, and reduced the CO and NO concentrations due to the combustion. 

The Effect of Swirl on the Velocity and Turbulence Fields of a Liquid Spray

1992 ◽  
Vol 114 (1) ◽  
pp. 72-81 ◽  
Author(s):  
A. Bren˜a de la Rosa ◽  
G. Wang ◽  
W. D. Bachalo
Keyword(s):  
Kinetic Energy ◽  
Swirling Flow ◽  
Energy Content ◽  
High Energy ◽  
Recirculation Region ◽  
Shear Stresses ◽  
Swirl Number ◽  
Double Peak ◽  
Mean Velocity ◽  
Liquid Spray

The work reports an experimental study of the effect of swirl on the structure of a liquid spray, i.e., on the behavior of drops and their interaction with the gaseous phase, and on the velocity and turbulence fields of the spray in the swirling flow. Three vane-type swirlers having low, medium, and high swirl numbers were used in the tests. The swirlers were placed on the liquid supply tube of a pressure atomizer and tested in the wind tunnel under specified conditions. Properties of the dispersed phase such as velocity and size distributions, particle number density, and volume flux were measured at several locations within the swirling flow field. In addition, mean velocity and turbulence properties were obtained for the gas phase. The results show that flow reversal of the drops is present at the high swirl number within the recirculation region. The spatial distribution of drops reveals a widening of the spray with increasing swirl strength while the concentration of large drops is shown to increase near the core of the swirling field with increasing swirl number. Plots of the turbulence kinetic energy, normal Reynolds stresses, and Reynolds shear stresses show double-peak radial distributions, which indicate regions in the flow where high energy content, mean velocity gradients, and large shear forces are present. The decay of turbulence velocities in the axial direction was observed to be very fast, an indication of high diffusion and dissipation rates of the kinetic energy of turbulence. The significance of the turbulence measurements is that these double-peak profiles indicate a deviation of the swirling spray from isotropy. This information should be relevant to researchers modeling these complex flows.

Strut Losses in a Diverging Annular Diffuser With Swirling Flow

2006 ◽  
Author(s):  
G. K. Feldcamp ◽  
A. M. Birk
Keyword(s):  
Total Pressure ◽  
Swirling Flow ◽  
Pressure Recovery ◽  
Swirl Number ◽  
Pressure Losses ◽  
Swirl Angle ◽  
Wide Range ◽  
Annular Diffuser ◽  
Inlet Swirl ◽  
The Ideal

An experimental investigation into the overall influence of struts spanning a double divergent annular diffuser followed by a straight cored annular diffuser has been undertaken in order to determine the performance of various strut configurations over a wide range of inlet swirl conditions. Two strut profiles have been investigated in four and eight strut configurations. Results have shown that the presence of struts under no swirl conditions have a relatively small effect on the overall total pressure loss. Increasing the inlet swirl angle to 20° has shown that the struts are able to assist in recovery of the swirling flow such that the pressure recovery nearly approaches that without struts, despite increased total pressure losses. Performance at 40° swirl is highly dependent on strut profile; the higher thickness-to-chord ratio strut configurations show minimal decrease in pressure recovery compared to 20° swirl, while the lower thickness-to-chord ratio configurations experiences a significant decrease as the result of significant flow separation from the struts. The exit swirl number has been shown to correlate strongly with the strut profile shape, while the number of struts had only a secondary influence. The exit velocity profiles show significant distortions at 40° swirl, and as a result the ideal pressure recovery calculated from the inlet and exit profiles change with strut configuration at 40° swirl.

The Influence of Orifice Insertion for Low Noxious Emissions from Combustion System

2014 ◽  
Vol 699 ◽  
pp. 684-688
Author(s):  
Mohamad Shaiful Ashrul Ishak ◽  
Mohammad Nazri Mohd Jaafar ◽  
Mohd. Amirul Amin Arizal ◽  
Norwazan Abdul Rahim ◽  
Mohammad Roslan Rahim ◽  
...  
Keyword(s):  
Area Ratio ◽  
Orifice Plate ◽  
Fuel Injector ◽  
Orifice Area ◽  
Back Plate ◽  
Air Mixing ◽  
Fuel Nozzle ◽  
Vane Angle ◽  
Outlet Orifice ◽  
Fuel Burner

This paper presents the effect of inserting swirler outlet orifice plate of different sizes at the exit plane of the radial air swirler in liquid fuel burner system. Tests were carried out with three different orifice plates with area ratios (orifice area to swirler exit area ratio) between 0.7 and 1.0 using 280 mm inside diameter combustor of 1000 mm length. Several tests were conducted using the commercial diesel as fuel. The fuel was injected at the back plate of the 45o vane angle swirler outlet using a central fuel injector with a single fuel nozzle pointing axially outwards. The aim of the insertion of orifice plates is to create the swirler pressure loss at the swirler outlet phase in order to maximise the swirler outlet shear layer turbulence to assist the fuel/air mixing. In the present work, the orifice plate with smaller area ratios exhibited very low NOX emissions for the whole operating equivalence ratios. The NOX reduction of more than 20 percent is achieved for orifice with 0.7 area ratio compared to 1.0 area ratio. Other emission such as carbon monoxide is increased with the decrease in the orifice area ratios. The results from this experiment show that good combustion is achieved by using smallest area ratios of orifice plate.

The Effect of Swirl on the Velocity and Turbulence Fields of a Liquid Spray

1990 ◽  
Author(s):  
A. Breña de la Rosa ◽  
G. Wang ◽  
W. D. Bachalo
Keyword(s):  
Kinetic Energy ◽  
Swirling Flow ◽  
Energy Content ◽  
High Energy ◽  
Recirculation Region ◽  
Shear Stresses ◽  
Swirl Number ◽  
Double Peak ◽  
Mean Velocity ◽  
Liquid Spray

This work reports an experimental study of the effect of swirl on the structure of a liquid spray, i.e., on the behaviour of drops and their interaction with the gaseous phase, and on the velocity and turbulence fields of the spray in the swirling flow. Three vane type swirlers having low, medium, and high swirl numbers were used in the tests. The swirlers were placed on the liquid supply tube of a pressure atomizer and tested in the wind tunnel under specified conditions. Properties of the dispersed phase such as velocity and size distributions, particle number density, and volume flux were measured at several locations within the swirling flow field. In addition, mean velocity and turbulence properties were obtained for the gas phase. The results show that flow reversal of the drops is present at the high swirl number within the recirculation region. The spatial distribution of drops reveals a widening of the spray with increasing swirl strength while the concentration of large drops is shown to increase near the core of the swirling field with increasing swirl number. Plots of the turbulence kinetic energy, normal Reynolds stresses, and Reynolds shear stresses show double-peak radial distributions which indicate regions in the flow where high energy content, mean velocity gradients, and large shear forces are present. The decay of turbulence velocities in the axial direction was observed to be very fast, an indication of high diffusion and dissipation rates of the kinetic energy of turbulence. The significance of the turbulence measurements is that these double peak profiles indicate a deviation of the swirling spray from isotropy. This information should be relevant to researchers modelling these complex flows.

An alternative approach to evaluate fuel/air mixing quality

2021 ◽  
pp. 1-15
Author(s):  
L.-Y. Jiang
Keyword(s):  
Temperature Variation ◽  
Practical Method ◽  
Maximum Temperature ◽  
Air Distribution ◽  
Ratio Distribution ◽  
Alternative Approach ◽  
Low Emission ◽  
Mixing Quality ◽  
Mixer Design ◽  
Air Mixing

ABSTRACT A practical method to evaluate quantitatively the uniformity of fuel/air mixing is essential for research and development of advanced low-emission combustion systems. Typically, this is characterised by measuring an unmixedness parameter or a uniformity index. An alternative approach, based on the fuel/air equivalence ratio distribution, is proposed and demonstrated in a simple methane/air venturi mixer. This approach has two main advantages: it is correlated with the fuel/air mixture combustion temperature, and the maximum temperature variation caused by fuel/air non-uniformity can be estimated. Because of these, it can be used as a criterion to check fuel/air mixing quality, or as a target for fuel/air mixer design with acceptable maximum temperature variation. For the situations where the fuel/air distribution non-uniqueness issue becomes important for fuel/air mixing check or mixer design, an additional statistical supplementary criterion should also be used.

Performance characteristics of flow in annular diffuser using CFD

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hardial Singh ◽  
Bharat Bhushan Arora
Keyword(s):  
Swirling Flow ◽  
Flow Behavior ◽  
Pressure Recovery ◽  
Ansys Fluent ◽  
Pressure Loss Coefficient ◽  
Swirl Angle ◽  
Swirl Intensity ◽  
Annular Diffuser ◽  
Inlet Swirl ◽  
Total Pressure Loss Coefficient

Abstract An annular diffuser is a critical component of the turbomachinery, and its prime function is to reduce the flow velocity. The current work is carried to study the effect of four different geometrical designs of an annular diffuser using the ANSYS Fluent. The numerical simulations were carried out to examine the effect of fully developed turbulent swirling and non-swirling flow. The flow behavior of the annular diffuser is analyzed at Reynolds number 2.5 × 105. The simulated results reveal pressure recovery improvement at the casing wall with adequate swirl intensity at the diffuser inlet. Swirl intensity suppresses the flow separation on the casing and moves the flow from the hub wall to the casing wall of the annulus region. The results also show that the Equal Hub and Diverging Casing (EHDC) annular diffuser in comparison to other diffusers has a higher static pressure recovery (C p  = 0.76) and a lower total pressure loss coefficient of (C L  = 0.12) at a 17° swirl angle.

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