Grid-Independent Boundary Layer Modeling for Swirling Thermofluid Channels
A comparative study of SST and detached eddy simulation (DES) for heat-transfer enhancement in corrugated heat exchangers.
Research
Computational fluid dynamics
Turbulence, boundary layers, multiphase flow and conjugate heat transfer, modelled in ANSYS Fluent.
Why it matters
Computational fluid dynamics (CFD) solves the equations of fluid motion on a computer mesh. It shows velocity, pressure and temperature in places a sensor cannot reach, and it lets a design change before anything is built. Thermofluids is the wider field that adds heat transfer and thermodynamics, which engines, heat exchangers and boilers all depend on.
The price of that detail is that an answer is only as good as its set-up. The mesh, the turbulence model and the boundary conditions all shape the result, which is why SciHeart keeps its checks in one place, the computational lab.
What we study
- Turbulence modelling
- Most engineering flows are turbulent. Resolving every eddy is possible only for small, simple cases, so a turbulence model stands in for the eddies that a mesh cannot resolve, and the right choice depends on the flow.
- Boundary-layer shear stress
- The thin layer of fluid against a wall sets the wall shear stress, which in turn governs drag and heat transfer. Capturing it takes a fine mesh at the wall, and an error there carries into the heat-transfer result.
- Multiphase flows
- Flows that carry more than one phase at once, such as gas bubbles in a liquid or droplets in a gas. The boundary between the phases is what makes them hard to model.
- Conjugate heat transfer
- Heat conducted through a solid wall while a fluid carries it away, solved together in one model. It is central to heat exchangers and engine cooling.
Where it is applied
- Heat exchangers. Corrugated surfaces and swirling flow in channels. Mixing the fluid and thinning the boundary layer can raise heat transfer, at the cost of a higher pressure drop.
- Engines. Flow and combustion inside the cylinder, linked to the work on clean combustion.
- Fuel and bioenergy systems. Liquid fuels, gaseous hydrogen and air moving through engines and process equipment, with chemical kinetics added where burning is involved.
How we work
- Solver. ANSYS Fluent, for thermofluid, turbulent and multiphase cases.
- Checks. Cases are checked against the protocols of the computational lab where they apply. CFD set-up for clients is described under simulation engineering.
Research topic