Computational fluid dynamics within energy conversion and food processing

SNIC 2017/1-591


SNAC Medium

Principal Investigator:

Johan Revstedt


Lunds universitet

Start Date:


End Date:


Primary Classification:

20306: Fluid Mechanics and Acoustics



This application is connected to our research activities within energy conversion related to rotating machinery (mainly wind turbines) and our activities related to the processing of liquid foods. Hence, the is a large span of challenges in these studies ranging simulating turbulent flows with very wide range of scales (atmospheric boundary layers) over fluid-structure interactions to rheologically complex multiphase flows. Usually horizontal axis wind turbines have three or four blades with some airfoil shape. However, as turbines are getting larger the size of the blades becomes an issue from a structural perspective. The purpose of our project is to, together with Structural Mechanics, LTH and Winfoor AB, investigate a new multi-aerofoil blade design. This will alter the aerodynamics of the blades and the turbine. We perform detailed flow simulations of these new designs to understand how they behave aerodynamically. Also, FSI studies of the blades will also be performed. Since the dynamics of the blade loading and interaction is of importance this will require the use of LES or DES. The main problems related to wind-turbines in cold climate include the uncertainties related to incoming wind (mean, turbulence and gusts), terrain, seasonal variations and ice-accretion during certain seasons/periods. The overall aims of the proposed project are to improve the understanding of the complex interaction of wind turbine performance, acoustic noise, ice accretion, blade heating and blade vibrations, and to utilize this knowledge to develop numerical tools for assessing and optimizing wind turbine performance in cold climate conditions. The main idea with this food processing project is to initiate a paradigm shift and no longer assume that the flow pattern for particular foods in the rheometer represents the flow pattern in the processing line. Instead the detailed flow pattern in both rheometer and the process line will be simulated by CFD, taking both the continuous phase rheological and the particles tribological properties into account. Hence, performing detailed simulations of the flow and particle interactions. This requires that the flow field around the particles is resolved. To achieve this one may employ interface tracking methods such as immersed boundary methods. Since the boundary layer around each particle needs to be resolved these types of simulations becomes computationally expensive when considering a large number of particles Vibrations in a compressor blade can originate from several sources, of which some are related to the geometry such as unsteadiness due to the upstream and downstream guide vanes, others are flow related and can for instance originate from separation of the flow on the blade, for example induced by shock waves. Unsteady forces acting on the blade will of course induce unsteady deformations (vibrations). The main objective of this work is to study the interaction between the rotor blades of the first compressor stage and the turbulent flow in transonic conditions using detailed turbulence models such as LES and DES. The scope of the proposed work includes aeroelastic simulations of the compressor stage using either LES of DES.