Non-premixed combustion in rotary kilns using Open-FOAM: the effect of conjugate heat transfer and external radiative heat loss on the reacting flow and the wall

Abbassi, M. El; Fikri, Dimas Dimas Ramadhan Abdillah; Lahaye, Domenico; Vuik, C.

doi:10.1615/thmt-18.1290

Cited by 3 publications

(2 citation statements)

References 8 publications

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“…This absorption causes the peak temperature in the flame to change. We modeled this effect in [21]. The change of peak temperature is important to consider in the modeling of thermal NOx formation.…”

Section: Conditions On the Freeboard-lining Interfacementioning

confidence: 99%

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

Lahaye

Abbassi

Vuik

et al. 2020

Fluids

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This work studies how non-premixed turbulent combustion in a rotary kiln depends on the geometry of the secondary air inlet channel. We target a kiln in which temperatures can reach values above 1800 degrees Kelvin. Monitoring and possible mitigation of the thermal nitric-oxide (NOx) formation is of utmost importance. The performed reactive flow simulations result in detailed maps of the spatial distribution of the flow, thermodynamics and chemical conditions of the kiln. These maps provide valuable information to the operator of the kiln. The simulations show the difference between the existing and the newly proposed geometry of the secondary air inlet. In the existing configuration, the secondary air inlet is rectangular and located above the base of the burner pipe. The secondary air flows into the furnace from the top of the flame. The heat release by combustion is unevenly distributed throughout the flame. In the new geometry, the secondary air inlet is an annular ring placed around the burner pipe. The secondary air flows circumferentially around the burner pipe. The new secondary air inlet geometry is shown to result in a more homogeneous spatial distribution of the heat release throughout the flame. The peak temperatures of the flame and the production of thermal NOx are significantly reduced. Further research is required to resolve limitations of various choices in our modeling approach.

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Section: Conditions On the Freeboard-lining Interfacementioning

confidence: 99%

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

Lahaye

Abbassi

Vuik

et al. 2020

Fluids

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“…E.g., in [4] we see how CFD can aid in the operation and design of a kiln to meet the specified requirements. We extended this model in [5] by adding the refractory lining, to allow the wall temperature to develop more realistically. Some other recent CFD studies related to rotary kilns include the modeling of the aerodynamics [6], combustion [7][8][9][10], multiphase flow [11], coupling with 1D material bed model [12], heat transfer coupled with DEM for granular flow [13,14], and combinations hereof [15,16].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Variable Air–Fuel Ratio on Thermal NOx Emissions and Numerical Flow Stability in Rotary Kilns Using Non-Premixed Combustion

2021

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One of the quickest ways to influence both the wall temperature and thermal NOx emissions in rotary kilns is to change the air–fuel ratio (AFR). The normalized counterpart of the AFR, the equivalence ratio, is usually associated with premixed flames and studies of its influence on diffusion flames are inconsistent, depending on the application. In this paper, the influence of the AFR is investigated numerically for rotary kilns by conducting steady-state simulations. We first conduct three-dimensional simulations where we encounter statistically unstable flow at high inflow conditions, which may be caused by vortex stretching. As vortex stretching vanishes in two-dimensional flow, the 2D simulations no longer encounter convergence problems. The impact of this simplification is shown to be acceptable for the thermal behaviour. It is shown that both the wall temperature and thermal NOx emissions peak at the fuel-rich and fuel-lean side of the stoichiometric AFR, respectively. If the AFR continues to increase, the wall temperature decreases significantly and thermal NOx emissions drop dramatically. The NOx validation, however, shows different results and indicates that the simulation model is simplified too much, as the measured NOx formation peaks at significantly fuel-lean conditions.

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Investigating the potentials to improve the energy consumption of a lime rotary kiln using measurement and CFD simulation

et al. 2022

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Non-premixed combustion in rotary kilns using Open-FOAM: the effect of conjugate heat transfer and external radiative heat loss on the reacting flow and the wall

Cited by 3 publications

References 8 publications

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

The Effect of Variable Air–Fuel Ratio on Thermal NOx Emissions and Numerical Flow Stability in Rotary Kilns Using Non-Premixed Combustion

Investigating the potentials to improve the energy consumption of a lime rotary kiln using measurement and CFD simulation

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