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. 

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.

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.

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.

Effect of Velocity Variation at High Swirl on Axial Flow Development inside a Can Combustor

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
Mohamad Shaiful Ashrul Ishak ◽  
Mohammad Nazri Mohd. Jaafar
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Reverse Flow ◽  
Flow Behavior ◽  
Axial Flow ◽  
Internal Flow ◽  
Velocity Variation ◽  
Recirculation Region ◽  
Injection Velocity ◽  
Mixing Enhancement

The main purpose of this paper is to study the internal flow effect of varying the inlet velocities inside a combustor. The flow field inside the combustor is controlled by the liner shape and size, wall side holes shape, size and arrangement (primary, secondary and dilution holes), and primary air swirler configuration. 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. Four various injection velocities from 30m/s to 60m/s with radial vanes angle of 50 degree were used in this analysis to show velocity effect on the internal flow field. The flow behavior was investigated numerically using CFD solver Ansys 14.0. This study has provided the characteristic insight into the flow pattern inside the combustion chamber. Results show that the swirling action is augmented with the increase in the injection velocity, which leads to increase in core reverse flow, thus enhancing mixing of fuel and air in the combustion chamber.

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.

Effects of Scalloping on the Mixing Mechanisms of Forced Mixers With Highly Swirling Core Flow

2012 ◽  
Author(s):  
Alex Wright ◽  
Zhijun Lei ◽  
Ali Mahallati ◽  
Mark Cunningham ◽  
Julio Militzer
Keyword(s):  
Swirling Flow ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Suction Surface ◽  
Reduced Pressure ◽  
Core Flow ◽  
Pressure Losses ◽  
Swirl Angle ◽  
Inlet Swirl ◽  
Mixing Rates

This paper presents a detailed experimental and computational investigation of the effects of scalloping on the mixing mechanisms of a scaled 12-lobe turbofan mixer. Scalloping was achieved by eliminating approximately 70% of the lobe sidewall area. Measurements were made downstream of the mixer in a co-annular wind tunnel and the simulations were carried out using an unstructured RANS solver, Numeca FINE/Hexa, with k-ω SST model. In the core flow, the swirl angle was varied from 0° to 30°. At high swirl angles, a three-dimensional separation bubble was formed on the lobe’s suction surface penetration region and resulted in the generation of a vortex at the lobe valley. The valley vortex quickly dissipated downstream. Most of the swirl was removed by the lobes, but scalloping allowed residual swirl to persist downstream of the mixer. The interaction of the swirling flow and the vortices resulted in improved mixing rates for the scalloped mixer. Inlet swirl up to 10° provided improved mixing rates, reduced pressure loss and thrust loss for both mixers. High inlet swirl resulted in improved mixing but produced higher pressure and thrust losses as compared to the zero swirl case. At high swirl, the scalloped mixer resulted in better mixing and lower pressure losses than the unscalloped mixer, but at the expense of reduced thrust.

scholarly journals Kinematic Measurements of Novel Chaotic Micromixers to Enhance Mixing Performances at Low Reynolds Numbers: Comparative Study

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 364
Author(s):  
Toufik Tayeb Naas ◽  
Shakhawat Hossain ◽  
Muhammad Aslam ◽  
Arifur Rahman ◽  
A. S. M. Hoque ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Flow Behavior ◽  
Reynolds Numbers ◽  
Comparative Investigation ◽  
Mixing Enhancement ◽  
Passive Mixer ◽  
Low Reynolds Numbers ◽  
Pressure Losses ◽  
Computational Evaluation ◽  
Low Reynolds

In this work, a comparative investigation of chaotic flow behavior inside multi-layer crossing channels was numerically carried out to select suitable micromixers. New micromixers were proposed and compared with an efficient passive mixer called a Two-Layer Crossing Channel Micromixer (TLCCM), which was investigated recently. The computational evaluation was a concern to the mixing enhancement and kinematic measurements, such as vorticity, deformation, stretching, and folding rates for various low Reynolds number regimes. The 3D continuity, momentum, and species transport equations were solved by a Fluent ANSYS CFD code. For various cases of fluid regimes (0.1 to 25 values of Reynolds number), the new configuration displayed a mixing enhancement of 40%–60% relative to that obtained in the older TLCCM in terms of kinematic measurement, which was studied recently. The results revealed that all proposed micromixers have a strong secondary flow, which significantly enhances the fluid kinematic performances at low Reynolds numbers. The visualization of mass fraction and path-lines presents that the TLCCM configuration is inefficient at low Reynolds numbers, while the new designs exhibit rapid mixing with lower pressure losses. Thus, it can be used to enhance the homogenization in several microfluidic systems.

Design of a Turbopiston Pump Guided by Computational Analysis

2019 ◽  
Author(s):  
Ting Wang ◽  
Patrick W. Rousset
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Flow Behavior ◽  
Original Design ◽  
Ansys Fluent ◽  
Pressure Losses ◽  
Sliding Mesh ◽  
Positive Displacement ◽  
Static Pressure Distribution ◽  
Large Flow

Abstract An innovative pump, TurboPiston Pump (TPP), has been invented to incorporate the merits of centrifugal, axial, and positive displacement pumps. The TPP is designed to deliver large flow rates with a potential at high pressure of up to 1000 psia with one stage. To improve the original design, an understanding of the flow behavior inside the pump is needed. The objective of this study is to simulate the flow field inside the pump and study its performance to guide the design process. This study includes modeling the pump with the transient sliding mesh scheme using a commercial computational fluid dynamics solver, ANSYS/FLUENT. The flow pattern, static pressure distribution, and total pressure losses are calculated and analyzed. The regions of high total pressure losses and potential creation of cavitation are identified. A plastic demonstration model and a metal prototype have been fabricated based on the result of the CFD analyis.

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