An improved correlation on the onset of heat transfer deterioration in supercritical water

Ma, Dengke; Zhou, Tao; Li, Bing; Shahzad, Muhammad Ali

doi:10.1016/j.nucengdes.2017.11.026

Cited by 23 publications

(2 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This deterioration may be the result of a significant density variation near the critical point that deforms the velocity profile, flagging the turbulence [5], or even due to the thickening of the viscous underlayer depending on the fluid flow rate [40]. Many research works, mainly performed numerically, have been published on this phenomenon, known as heat transfer deterioration (HTD) [41][42][43][44][45][46][47]. Recently, Wang et al [48] obtained, by simulation, that semicircular heating decreased the degree of HTD due to the greater turbulence produced by the greater density difference between the heating side and the adiabatic side.…”

Section: Heat Transfer Deterioration In Scwg Experimentsmentioning

confidence: 99%

Heat Transfer Limitations in Supercritical Water Gasification

et al. 2021

View full text Add to dashboard Cite

Supercritical water gasification (SCWG) is a promising technology for the valorization of wet biomass with a high-water content, which has attracted increasing interest. Many experimental studies have been carried out using conventional heating equipment at lab scale, where researchers try to obtain insight into the process. However, heat transfer from the energy source to the fluid stream entering the reactor may be ineffective, so slow heating occurs that produces a series of undesirable reactions, especially char formation and tar formation. This paper reviews the limitations due to different factors affecting heat transfer, such as low Reynolds numbers or laminar flow regimes, unknown real fluid temperature as this is usually measured on the tubing surface, the strong change in physical properties of water from subcritical to supercritical that boosts a deterioration in heat transfer, and the insufficient mixing, among others. In addition, some troubleshooting and new perspectives in the design of efficient and effective devices are described and proposed to enhance heat transfer, which is an essential aspect in the experimental studies of SCWG to move it forward to a larger scale.

show abstract

Section: Heat Transfer Deterioration In Scwg Experimentsmentioning

confidence: 99%

Heat Transfer Limitations in Supercritical Water Gasification

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Pandey et al [27] improved the ability to predict the HTD by the two-layer model. Ma et al [28] put forward a new form of correlation to predict the heat flux at which the HTD occurs based on different working conditions. Pioro et al [29] deemed that there is only one correlation that can accurately assess the occurrence of the HTD and its magnitude.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of supercritical n-decane upward flow and heat transfer characteristics in the buffer layer of a vertical tube

Sun

Xie

et al. 2019

Numerical Heat Transfer, Part A: Applications

View full text Add to dashboard Cite

To explore the behavior and mechanisms of heat transfer deterioration (HTD), the flow and thermal performances of supercritical n-decane in upward vertical tubes are investigated with emphasis on the boundary layer. It is realized that the dramatic variation of the thermophysical properties can cause unconventional heat transfer phenomenon and the change of the density is important in particular. The intensity of the HTD gradually increases once the position of the pseudo-critical temperature lays in the buffer layer region. Correspondingly, the turbulence kinetic energy is significantly suppressed. The large temperature gradient in the buffer layer zone means that the temperature commonly used in existing empirical correlations and based on the wall temperature or bulk temperature is not very appropriate and such an approach leads to poor prediction accuracy of the correlations.

show abstract