Derivation of a Look-Up Table for Trans-Critical Heat Transfer for Water-Cooled Tubes
NURETH-14 - 2011 September 25-30


Presented at:
NURETH-14
2011 September 25-30
Location:
Toronto, Canada
Session Title:
A12-5 Thermalhydraulics of High Prandtl-Number (Supercritical) Flows (II)

Authors:
Hussam Zahlan (University of Ottawa)
De Groeneveld (University of Ottawa)
Stavros Tavoularis (University of Ottawa)
  

Abstract

A trans-critical look-up table (LUT) provides predictions of heat transfer for the region near and

beyond the critical point for water. The trans-critical LUT starts at the high subcritical pressure

of 19 MPa and extends to supercritical pressures, up to 30 MPa. The intended range of

application of the LUT is sufficiently wide to fit all conditions for which conventional singlephase

correlations do not apply. This article describes the progress made in deriving a transcritical

LUT for tubes cooled by vertical upflow of high-pressure water.

The University of Ottawa (UO) team has compiled a large trans-critical water database and

combined it with supercritical water (SCW) databases from other organizations. The expanded

database has been carefully examined and duplicate data as well as obvious outliers and data not

satisfying a heat balance have been removed. The expanded UO database includes more than

25,000 screened data points.

A literature review has been performed in parallel with the LUT compilation and has identified

18 single-phase, near-critical and supercritical (SC) heat transfer correlations. The predictions of

these correlations have been compared to the experimental values of the UO expanded database

and a statistical error analysis of the comparison results has been performed. The parametric

trends of the uncertainty of the more promising correlations are described in this paper.

A skeleton LUT has been constructed in which the heat transfer coefficients are assumed to be

unique functions of pressure, mass flux, heat flux (or surface temperature) and fluid enthalpy; the

LUT domain has been subdivided into sub-domains, each associated with a distinct heat transfer

mechanism. The sub-domains include high pressure subcritical regions (liquid, subcritical

vapor, and subcritical two-phase regions), SC regions (high-density state or SC liquid-like

region, and low-density state or SC vapor-like region) and a near-critical or near-pseudo-critical

region. For each region, the best correlations were identified and subsequently used for the

construction of the skeleton LUT, which will be updated by experimental data suitably

normalized. The parametric trends of the skeleton table have been examined and compared to

experimental data.

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