[mullenc525]

I’m doing some heat exchanger design, and would like some advice on turbulence modeling. I run on a PC with 4gb ram and a quad 2.4 ghz processor. I’ve attached an image with example geometries - flow field elements on top and 'periodic repeated' mesh volumes on bottom.

The length of the channels (streamwise, or x) will be about 20cm, width (z) about 5-10 cm, and height (y) 0.5-2mm.

In the pin field, pins are ~1mm dia on 3mm spacing. In the rib design, ribs are 1mm square with 4mm z spacing, and the lateral support webs are 0.25mm in y and 2mm in x, spaced 20mm in x.

In both geometry cases, I want to understand the effects the blunt bodies in the channel have on turbulence and heat transfer. The fluid is air at ~6m/s, so Re are 200-800 based on height.

I'm happy to assume fully developed flow along the length of the device, so that makes the repeating units quite small [3mm,0.5-2mm,50-100mm] for the pin field or [20mm,0.5-2mm,20mm] for the rib design.

From my limited understanding of CFD:

1. I can't use a laminar model since there is gross flow separation
2. Turbulent models don't relaminarize for example after the lateral web in the rib design
3. Turbulent models with transition are custom tailored for external flows and therefore not appropriate

However, the Re is low and domain is very small. Will LES be feasible for this, and is this the best choice for me?