A Logarithmic Turbulent Heat Transfer Model in Applications with Liquid Metals for Pr = 0.01–0.025

Abstract

The study of turbulent heat transfer in liquid metal flows has gained interest because of applications in several industrial fields. The common assumption of similarity between the dynamical and thermal turbulence, namely, the Reynolds analogy, has been proven to be invalid for these fluids. Many methods have been proposed in order to overcome the difficulties encountered in a proper definition of the turbulent heat flux, such as global or local correlations for the turbulent Prandtl number and four parameter turbulence models. In this work we assess a four parameter logarithmic turbulence model for liquid metals based on the Reynolds Averaged Navier-Stokes (RAN) approach. Several simulation results considering fluids with P r = 0.01 and P r = 0.025 are reported in order to show the validity of this approach. The Kays turbulence model is also assessed and compared with integral heat transfer correlations for a wide range of Peclet numbers.

A New Anisotropic Four-Parameter Turbulence Model for Low Prandtl Number Fluids

“…In Table 1, we report the expansion for the mean and fluctuating velocity and temperature. Following the definitions ( 6) and (15), we obtain the following dynamical turbulence variable expansions:…”

“…Numerical simulations have been performed for the forced convection calculations using the anisotropic four-parameter turbulence model (A4P) and the results are compared in the next subsections with DNS data and with the results from numerical simulations using the standard isotropic four-parameter model (4P) [4,[13][14][15][16]37].…”

“…In [11], the thermal model has been coupled with a low-Reynolds linear k-ε model, while in [12], the coupling with a second-order Reynolds stress model has shown better results. In [13][14][15][16], an isotropic four-parameter model has been proposed. The model introduces two additional thermal transport equations for the evaluation of the squared temperature fluctuations k θ and its dissipation ε θ .…”

“…Plane channel simulations for several Re τ and Pr = 0.01, 0.025 have been successfully performed [13,14,16]. Numerical simulations in forced and mixed convection regimes are very promising for the backward-facing step configuration [15], however the adoption of an anisotropic formulation is required to improve the prediction of turbulent heat flux components.…”

Turbulent Flow over Confined Backward-Facing Step: PIV vs. DNS

“…The BFS geometry in SESAME project was considered in a liquid metal experiment [2] at the same Reynolds number 7100, which included the heated section at the same position as in DNS of Oder et al [2]. Such low Reynolds numbers are relevant for liquid metal reactors [3], where low flow rates are foreseen due to the superb heat transfer characteristics of the coolants. Since the final geometry and the Reynolds number of liquid metal experiment [4] were slightly different than in DNS, the second BFS experiment related to the SESAME project was developed: adiabatic experiment performed with water and without heating.…”