Computational Fluid Dynamics
for fans and plants – Part 2

1 Parameterized layout with modification

2 Adapted 3D models

3 Unstructured computational mesh

4 Block-structured hexahedral mesh

5 Flow profile

6 Boundary layer discretization with vector arrows

7 ANSYS CFX-Pre

8 ANSYS CFX Solver

9 ANSYS CFX Post

17 System arrangement drawing with induced draught fan

18 3D model of the induced draught fan

19 Flow lines

20 Total pressure profile with original design

21 Strong swirl with original design

22 Total pressure profile after optimizing design

23 Swirl after optimizing design

24 Flow lines of original design

25 Flow lines of optimized design

10 Stack geometry with marked problem zone

11 Velocity distribution in stack

12 Pressure pattern at measuring points

13 Original geometry

14 Duct with baffle plates

15 Velocity with optimized geometry

16 Pressure gradient with baffle plates

26 Geometry DHRV 50B-2000

27 Mesh of DHRV 50B-2000 with detail of leading edges of impeller blades

28 Specification of the boundary conditions

29 Solution of the differential equations

30 Flow line diagram

Summary: After the mathematical fundamentals of the computational fluid dynamics (CFD) as well as the implementation and applications of CFD simulations had been dealt with in part 1 (ZKG 05/2011, p. 48), the second part deals with the description of examples of application for the optimization of large fans. The article is complemented by simulations on the web site www.zkg.de/fans .

1 Introduction

Computational Fluid Dynamics (CFD) is a method that is used for the computerized calculation of technical flows with state-of-the-art accuracy. With this method, it is possible to make far more precise statements regarding the behaviour of a technical or natural flow than could be made on the basis of classical partly-empirical, test-based approaches. CFD has been employed on an economic scale since around 1973, when it was first applied in the aircraft construction sector. The underlying partial differential equations according to Navier-Stokes, which precisely describe the flow...