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Ebook Engineering analysis with ANSYS: Part 2

(BQ) Part 2 book "Engineering analysis with ANSYS" has contents: Analysis for fluid dynamics, application of ANSYS to thermo mechanics, application of ANSYS to contact between machine elements. | Chapter 5 Analysis for Fluid Dynamics Chapter outline 5.1 5.2 5.3 5.1 Introduction Analysis of flow structure in a diffuser Analysis of flow structure in a channel with a butterfly valve 215 216 242 Introduction arious fluids such as air and liquid are used as an operating fluid in a blower, a compressor, and a pump. The shape of flow channel often determines the efficiency of these machines. In this chapter, the flow structures in a diffuser and the channel with a butterfly valve are examined by using FLOTRAN which is an assistant program of ANSYS. A diffuser is usually used for increasing the static pressure by reducing the fluid velocity and the diffuser can be easily found in a centrifugal pump as shown in Figure 5.1. V Flow Blades Diffuser Figure 5.1 Typical machines for fluid. 215 216 Chapter 5 Analysis for fluid dynamics 5.2 5.2.1 Analysis of flow structure in a diffuser Problem description Analyze the flow structure of an axisymmetric conical diffuser with diffuser angle 2θ = 6◦ and expansion ratio = 4 as shown in Figure 5.2. y 2θ = 6° x 4.5DE Straight channel for entrance Figure 5.2 9.55DE Diffuser region 50DE Straight channel for exit Axisymmetrical conical diffuser. Shape of the flow channel: (1) Diffuser shape is axisymmetric and conical, diffuser angle 2θ = 6◦ , expansion ratio = 4. (2) Diameter of entrance of the diffuser: DE = 0.2 m. (3) Length of straight channel for entrance: 4.5DE . (4) Length of diffuser region: 9.55DE . (5) Length of straight channel for exit: 50.0DE . Operating fluid: Air (300 K) Flow field: Turbulence Velocity at the entrance: 20 m/s Reynolds number: 2.54 × 105 (assumed to set the diameter of the diffuser entrance to a representative length) Boundary conditions: (1) Velocities in all directions are zero on all walls. (2) Pressure is equal to zero at the exit. (3) Velocity in the y direction is zero on the x-axis. 5.2.2 Create a model for analysis 5.2.2.1 Command SELECT KIND OF ANALYSIS ANSYS Main Menu → .