Abstract
This paper presents the results of measurements and numerical predictions of turbulent cross-flow through an in-line 7×7 bundle configuration with a constant transverse and longitudinal pitch-to-diameter ratio of 1.44. The experiments are conducted to measure the pressure around tubes, using DPS differential pressure scanner with air flow, in square channel at a Reynolds number of 35000 based on the gap velocity and the tube diameter. The commercial ANSYS FLUENT is used to solve the unsteady Reynolds–Averaged Navier–Stokes (RANS) equations. The primary aim of the present study is to search for a turbulent model that could serve as an engineering design tool at a relatively low computational cost. The performances of the Spalart-Allmaras, the RNG k-ε, the Shear Stress Transport k-ω and the second moment closure RSM models are evaluated by comparing their simulation results against experimental data. The second objective is to verify the validity of the periodicity assumption taken account in the most previous numerical works by considering the filled bundle geometry. The CFD results show that the Spalart-Allmaras model on the fine mesh are comparable to the experiments while the periodicity statement did not produce consistently the flow behavior in the 7×7 tube bundle configuration.
Highlights
Flow in tube bundles have many important industrial applications and have been studied both experimentally and through numerical simulations
This paper presents the results of measurements and numerical predictions of turbulent cross-flow through an in-line 7×7 bundle configuration with a constant transverse and longitudinal pitch-to-diameter ratio of 1.44
They explain that the hysteresis comes from a bending of solution branch due to non-linear interactions of the wake with the downstream tube, which leads to two stable oscillatory solution branches connected to each other through an unstable solution branch
Summary
Flow in tube bundles have many important industrial applications and have been studied both experimentally and through numerical simulations. Rollet-Miet et al [6] use the LES technique and the k–İ model to predict the turbulent flow as produced by the experiment of Simonin and Barcouda [2]. Both LES and k–İ models calculate the mean velocity profiles reasonably well while k–İ model gives poor predictions of the Reynolds stresses in the wake region inconsistency to the LES results. Imran [13] studies the turbulent flow through square in-line arrays using various RANS and LES simulations Several flow parameters such as velocity profiles, pressure distributions, instantaneous and RMS lift and drag coefficients and Reynolds stresses are compared to the available experimental data. The pressure distribution on the tube surface indicates the stagnation pressure region located somewhere around 45o to the LES results of Imran [13]
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