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Journal ArticleDOI

A review on recent heat transfer studies to supercritical pressure water in channels

TL;DR: In this article, a large amount of experimental data were obtained from the experiments supplementing the extensive database previously compiled for fossil fuel-fired power plants, and prediction methods for heat-transfer coefficient were developed from various databases.
About: This article is published in Applied Thermal Engineering.The article was published on 2018-09-01. It has received 80 citations till now. The article focuses on the topics: Heat transfer & Large eddy simulation.
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Journal ArticleDOI
TL;DR: In this article, the authors presented a general supercritical heat transfer (SHT) correlation for advanced power cycles, where the pseud-boiling assumption is introduced to deal with SHT.

51 citations

Journal ArticleDOI
TL;DR: In this paper, the characteristics of abnormal heat transfer of supercritical carbon dioxide (SCO2) at various ranges of mass flow rate in heated vertical-flow tube were investigated, and a new correlation was developed based on the heat transfer data more than 2800 which sets from 10 independent experiments.

50 citations

Journal ArticleDOI
TL;DR: In this paper, a new heat transfer correlation was developed for S-CO2 under high q/G conditions, in which buoyancy effect and variations in thermophysical properties were both taken into account.

47 citations

Journal ArticleDOI
Y.H. Fan1, Guihua Tang1, Xionghui Li1, D.L. Yang1, Shun-sen Wang1 
01 Mar 2019-Energy
TL;DR: In this article, the heat transfer characteristics of S-CO2 in circumferentially non-uniform heated vertical upward flow are numerically studied and the fundamental mechanisms are discussed.

39 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide basic background knowledge on trans-critical CO2 Rankine cycle in low-grade heat conversion and present a review of experimental tests and demonstrations on supercritical CO 2 operation considering heat-to-power systems.

37 citations

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Journal ArticleDOI
TL;DR: In this paper, the authors present a review of the applicability and applicability of numerical predictions of turbulent flow, and advocate that computational economy, range of applicability, and physical realism are best served by turbulence models in which the magnitudes of two turbulence quantities, the turbulence kinetic energy k and its dissipation rate ϵ, are calculated from transport equations solved simultaneously with those governing the mean flow behaviour.

11,866 citations

Proceedings ArticleDOI
06 Jul 1993
TL;DR: In this article, two versions of the k-w two-equation turbulence model are presented, the baseline model and the Shear-Stress Transport (SSn) model.
Abstract: Two new versions of the k - w two-equation turbulence model will be presented. The new Baseline (BSL) model is designed to give results similar to those of the original k - w model of Wilcox. but without its strong dependency on arbitrary freestream values. The BSL model is identical to the Wilcox model in the inner SOC7£; of the boundary-layer but changes gradually to the standard k - f. model (in a k - w fonnulation) towards the boundary-layer edge. The new model is also virtually identical to the k - f. model for free shear layers. The second version of the model is called Shear-Stress Transport (SSn model. It is a variation of the BSL model with the additional ability to account for the transport of the principal turbulent shear stress in adverse pressure gradient boundary-layers. The model is based on Bradshaw's assumption that the principal shear-stress is pro­ portional to the turbulent kinetic energy, which is introduced into the definition of the eddy-viscosity. Both models are tested for a large number of different fiowfields. The results of the BSL model are similar to those of the original k - w model, but without the undesirable free stream dependency. The predictions of the SST model are also independent of the freestrearn values but show better agreement with exper­ imental data for adverse pressure gradient boundary-layer flows.

2,470 citations

Journal ArticleDOI
TL;DR: In this article, a two-equation model and Reynolds stress transport model are developed for turbulent shear flows and tested for homogeneous shear flow and flow over a backward facing step.
Abstract: Turbulence models are developed by supplementing the renormalization group (RNG) approach of Yakhot and Orszag [J. Sci. Comput. 1, 3 (1986)] with scale expansions for the Reynolds stress and production of dissipation terms. The additional expansion parameter (η≡SK/■) is the ratio of the turbulent to mean strain time scale. While low‐order expansions appear to provide an adequate description for the Reynolds stress, no finite truncation of the expansion for the production of dissipation term in powers of η suffices−terms of all orders must be retained. Based on these ideas, a new two‐equation model and Reynolds stress transport model are developed for turbulent shear flows. The models are tested for homogeneous shear flow and flow over a backward facing step. Comparisons between the model predictions and experimental data are excellent.

2,347 citations

Journal ArticleDOI
TL;DR: Large Eddy Simulation (LES) is an approach to compute turbulent flows based on resolving the unsteady large-scale motion of the fluid while the impact of the small-scale turbulence on the large scales is accounted for by a sub-grid scale model as mentioned in this paper.
Abstract: Large Eddy Simulation (LES) is an approach to compute turbulent flows based on resolving the unsteady large-scale motion of the fluid while the impact of the small-scale turbulence on the large scales is accounted for by a sub-grid scale model. This model distinguishes LES from any other method and reduces the computational demands compared with a Direct Numerical Simulation. On the other hand, the cost typically is still at least an order of magnitude larger than for steady Reynolds-averaged computations. The LES approach is attractive when statistical turbulence models fail, when insight into the vortical dynamics or unsteady forces on a body is desired, or when additional features are involved such as large-scale mixing, particle transport, sound generation etc. In recent years the rapid increase of computer power has made LES accessible to a broader scientific community, and this is reflected in an abundance of papers on the method and its applications. Still, however, some fundamental aspects of LES are not conclusively settled, a fact residing in the intricate coupling between mathematical, physical, numerical and algorithmic issues. In this situation it is of great importance to gain an overview of the available approaches and techniques. Pierre Sagaut, in the style of a French encyclopedist, gives a very complete and exhaustive treatment of the different kinds of sub-grid scale models which have been developed so far. After discussing the separation into resolved and unresolved scales and its application to the Navier-Stokes equations, more than 140 pages are directly devoted to the description of sub-grid scale models. They are classified according to different criteria, which helps the reader to find his or her way through the arsenal of reasonings. The theoretical framework for which these models have mostly been developed is isotropic turbulence. The required notions from classical turbulence theory are summarized together with notions from EDQNM theory in two concise and helpful appendices. Further sections deal with numerical and implementational issues, boundary conditions and validation practice. A final section assembles a few key applications, cumulating in a condensed list of some general experiences gained so far. The book very wisely concentrates on issues particular to LES, which to a large extent is sub-grid scale modelling. Classical issues of CFD, such as numerical discretization schemes, solution procedures etc, or post-processing are not addressed. Limiting himself to incompressible, non-reactive flows, the author succeeds in describing the fundamental issues in great detail, thus laying the foundations for the understanding of more complex situations. The presentation is essentially theoretical and the reader should have some prior knowledge of turbulence theory and Fourier transforms. The text itself is well written and generally very clear. A pedagogical effort is made in several places, e.g. when an overview over a group of models is given before these are described in detail. A few typing errors and technical details should be amended in a second edition, though, such as the statement that a filter which is not a projector is invertible (p 12), but this is not detrimental to the quality of the text. Overall the book is a very relevant contribution to the field of LES and I read it with pleasure and benefit. It constitutes a worthy reference book for scientists and engineers interested in or practising LES and may serve as a textbook for a postgraduate course on the subject. Jochen Frohlich

771 citations

Journal ArticleDOI
K. Yamagata1, Kaneyasu Nishikawa1, Shu Hasegawa1, T. Fujii1, S Yoshida1 
TL;DR: In this article, a comprehensive set of data was obtained for pressures from 226 to 294 bar, bulk temperatures from 230 to 540°C, heat fluxes from 116 to 930 kW/m 2 and mass velocities from 310 to 1830 kg/m2s.

570 citations