Flow and heat transfer in a pin-fin array

Confined Flows

Underlying Flow Regime 4-18

Description

Introduction

Give a brief overview of the UFR in question. Describe the main characteristics of the type of flow. In particular, what are the underlying flow physics which characterise this UFR and must be captured by the CFD methods? If the UFR considered here is of special relevance for a particular AC featured in the KB, this should be mentioned.

Review of UFR studies and choice of test case

Provide a brief review of past studies of this UFR which have included test case comparisons of experimental measurements with CFD results. Identify your chosen study (or studies) on which the document will focus. State the test-case underlying the study and briefly explain how well this represents the UFR? Give reasons for this choice (e.g a well constructed test case, a recognised international comparison exercise, accurate measurements, good quality control, a rich variety of turbulence or physical models assessed etc.) . If possible, the study should be taken from established data bases. Indicate whether of not the experiments have been designed for the purpose of CFD validation (desirable but not mandatory)?

The experiments from Ames et al. test the flow of air around 8 staggered rows of 7.5 heated pins, spaced at P=2.5D in both stream-wise and span-wise directions (based on center to center distances). The diameter of the pins is set to 0.0254 m (1 inch) and the channel height is twice the diameter (H=2D). The Reynolds numbers $Re_{D}$ based on the pin diameter and the average gap bulk velocity are 3,000, 10,000 and 30,000 respectively. The gap bulk velocity is determined between two adjacent pins of the same row. Taking $V_{0}$ and $V_{G}$ as the inlet and gap velocities, respectively, and considering mass conservation, one obtains $V_{G}={\frac {P}{P-D}}$ . A sketch of the original experimental configuration is given in Figure 1. Several experiments have been carried out for the heat transfer measurements. For the current test case, the configuration with heated (constant heat-flux) bottom wall with adiabatic pins and top wall is chosen, same as in [5] and [6].