A computationally efficient P1 radiation model for modern combustion systems utilizing pre-conditioned conjugate gradient methods

Krishnamoorthy, Gautham

doi:10.1016/j.applthermaleng.2017.03.055

Cited by 25 publications

(9 citation statements)

References 52 publications

(60 reference statements)

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“…26 In the radiation model, the discrete ordinates model 16 and the P1 model 17 can be used to calculate the radiation heat transfer in the RSC. The P1 model can speed up the calculation convergence compared with the discrete ordinates model, 27 so the P1 model is employed in this work. The species transport model is used to simulate the multicomponent of the syngas.…”

Section: Model Descriptionmentioning

confidence: 99%

Numerical Simulation of Heat Transfer and a Forging Plate Structure in a Radiant Syngas Cooler with Radiation Screens

Qiu

Guo

Wei

et al. 2020

Ind. Eng. Chem. Res.

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High-temperature syngas is produced by entrained-flow coal gasification. A traditional quenching process has the drawback of low heat recovery efficiency, and the cleaning of convective syngas cooler is a big problem. Thus, the combination of a radiant syngas cooler and a quench chamber is a more promising way for heat recovery and syngas preliminary purification. In this study, based on the traditional radiant syngas cooler, sixteen radiation screens are added to increase the heat exchange area, so as to further improve heat recovery efficiency of the radiant syngas cooler. Heat transfer and structure analysis of a forging plate on the top of the radiation screen are carried out by numerical simulation. The radiation screen changes the internal spatial structure of the radiant syngas cooler, which also affects the heat transfer characteristics of the membrane wall. The circumferential temperature distribution of the cylinder membrane wall is not uniform, and the temperature is the highest at the central pipe. The surface heat flux of the cooling pipes on the radiation screen reaches the maximum value at the position with a distance of about 6 m from the top. The slag and fly ash carried in the gas flow deposit on the wall surface and form deposition layers, which protects the forging plate and cooling pipes, but reduces the heat transfer efficiency.

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Section: Model Descriptionmentioning

confidence: 99%

Numerical Simulation of Heat Transfer and a Forging Plate Structure in a Radiant Syngas Cooler with Radiation Screens

Qiu

Guo

Wei

et al. 2020

Ind. Eng. Chem. Res.

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“…The boundary conditions of the computational domain are shown in Table 3. For the radiation model, the P1 radiation model was used in this paper as referenced in [46]. In this study, in order to reduce the number of grids and the amount of calculations, we simplified the real building into a wall with a certain thickness that participated in convective heat transfer and radiative heat transfer.…”

Section: Mesh Division and Boundary Condition Parameter Settingsmentioning

confidence: 99%

A Study of Simulation of the Urban Space 3D Temperature Field at a Community Scale Based on High-Resolution Remote Sensing and CFD

Huo

Chen

2022

Remote Sensing

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This study used high-resolution remote-sensing technology and CFD models to carry out a simulation study of a three-dimensional (3D) USTE for daytime and nighttime at a block scale. Firstly, the influence of vegetation with different spatial layouts on the 3D USTE was analyzed. Moreover, the heat transfer process and heat conduction process between urban surface components at the block scale were simulated, and in the meanwhile, the distribution and changes of the 3D USTE and the regional wind pressure environment were monitored. The simulation results showed that (1) vegetation has a relatively significant mitigation effect on the thermal environment near the surface, (2) vegetation with different morphologies and layouts results in significant differences in the mitigation efficiency of wind speed and canyon USTE, and (3) the seasonal spatial 3D temperature can be mitigated as well. In addition, this study analyzed the mitigation effect of vegetation on the urban wind–heat environment during both daytime and nighttime. The results indicated that (1) the mitigation effect of vegetation is more significant during the daytime, while showing a small value at night with an even temperature distribution, and (2) convection heat transfer is the primary cause, or one of the major causes, of differences in the USTE.

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“…The simulations of radiant heat transfer are complicated. Previous studies have indicated that both the P1 model and the discrete ordinates model are suitable for the radiant heat transfer calculation in the industrial RSC, , but the calculation speed of the P1 model is faster than that of the discrete ordinates model . Therefore, the P1 model is employed to calculate the radiant heat transfer in the industrial RSC.…”

Section: Model Descriptionmentioning

confidence: 99%

Numerical Simulations of Solidification Characteristics of Molten Slag Droplets in Radiant Syngas Coolers for Entrained-Flow Coal Gasification

et al. 2021

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The high-temperature syngas and molten slag droplets discharged from entrained-flow coal gasifiers contain a large amount of heat energy, which can be efficiently recovered by radiant syngas coolers (RSCs). However, it is hard to know the solidification degree of molten slag droplets at the outlet of an RSC during industrial operations. In this work, the industrial-scale RSC and molten slag droplet models are established to predict the solidification degree of slag droplets at the outlet of the RSC. Then, the effects of slag diameter, syngas flow field, slag initial temperature, slag porosity, and slag pore structure are investigated by numerical simulations, and residence time as well as complete solidification time are calculated by coupling of a discrete-phase model and a solidification model. The results indicate that as the slag droplet diameter increases, the residence time of the slag droplet shortens, but the complete solidification time increases. When the slag droplet diameter is greater than or equal to 3.0 mm, the complete solidification time is larger than the residence time, and the slag droplet cannot solidify completely at the outlet of the RSC. The solidification degree in the windward zone is greater than that in the leeward zone. Although the slag initial temperature has little effect on the solidification, a lower slag initial temperature is still conducive to a greater solidification degree. Additionally, the pore structure facilitates solidification, and the promoting effect of penetrated pores is more remarkable than that of closed pores. A larger porosity is also beneficial to accelerate the solidification of molten slag droplets and increase the solidification degree.

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A computationally efficient P1 radiation model for modern combustion systems utilizing pre-conditioned conjugate gradient methods

Cited by 25 publications

References 52 publications

Numerical Simulation of Heat Transfer and a Forging Plate Structure in a Radiant Syngas Cooler with Radiation Screens

Numerical Simulation of Heat Transfer and a Forging Plate Structure in a Radiant Syngas Cooler with Radiation Screens

A Study of Simulation of the Urban Space 3D Temperature Field at a Community Scale Based on High-Resolution Remote Sensing and CFD

Numerical Simulations of Solidification Characteristics of Molten Slag Droplets in Radiant Syngas Coolers for Entrained-Flow Coal Gasification

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