An Improved nongray-wall emissivity-absorptivity model for the Full-Spectrum Correlated K-distribution method. (1st June 2022)

• Record Type: Journal Article
• Authors: Liu, Guanghai; Liu, Yuying; Zhu, Jinyu; Consalvi, Jean-louis; Liu, Fengshan
• Is Part Of: International journal of heat and mass transfer. Volume 188(2022)
• Publication Date: 2022-06-01
• Subjects: Radiative heat transfer -- Full-Spectrum Correlated K-distribution -- Nongray-wall -- Emissivity -- Absorptivity; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2022.122604
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: An improved nongray-wall emissivity-absorptivity model for FSCK is proposed. It is more accurate than the original model when wall-to-wall radiation is important. It is less sensitive to the effective mean temperature than the original model. Abstract: In practical combustion chambers, the emissivity of wall materials in general varies spectrally and inappropriate treatments may lead to significant errors in modeling radiative heat transfer. To reduce the error of the Full-Spectrum Correlated K-distribution (FSCK) method in practical problems involving nongray walls, a nongray-wall model is proposed by reordering the wall emissivity and absorptivity separately, in which the Planck function at the wall temperature and an effective mean temperature is used as the weight function of wall emissivity and absorptivity, respectively. As a result, this new model preserves the wall emission and considers the spectral radiative property of the wall. Radiative heat transfer calculations in 1D and 3D configurations bounded by nongray walls are simulated to evaluate the accuracy of this new model. The results show that this new model is in general more accurate than the recently developed nongray-wall model (Liu et al., Int. J. Heat Mass Transf. 2021), especially in cases where the wall-to-wall radiative heat transfer plays an important role. It is also showed that this new model is less sensitive to the choice of the effective mean temperature and the medium blackbody emission-averaged temperature is recommended.