4.2. Impeller design

3.4. Finite volume discretization method(FVDM)

104 Numerical Simulations in Engineering and Science

volumes.

downstream components.

4.1. Centrifugal compressor specifications

Paullay during 1970s. The basic structure of the FVM is as follows:

1. The physical problem is discretized into control volumes.

4. Case study: Design of the centrifugal compressor

Any fluid flow problem can be solved with high resolution when the basic concept of continuum is considered during the numerical solution methodology. Finite volume discretization method (FVDM/FVM) is one such methodology developed by McDonald, MacCormack, and

4. Nodal value interpolations are used to approximate the derivatives and function values. 5. The solution is achieved by assembling the algebraic systems of the discrete control

The case study presented in the literature [5] is considered for the present illustration for the design and numerical analysis of the centrifugal compressor. Main objective of the current work is to design a centrifugal compressor capable of delivering a pressure ratio of 5.4 with a mass flow ingestion rate of 5.73 kg/sec. The compressor is targeted to achieve 82% total-total efficiency with design constraints of 280 mm for the impeller and 340 mm for the diffuser in terms of diameter. Also, the compressor has to generate flow parameters relative to functional

2. Each control volume is formulated with balance equations involving integrals.

3. Numerical integration is applied to approximate the integral equations.

The input parameters of the centrifugal compressor are tabulated in Table 1.

Table 1. Geometrical and functional specifications of analysed turbo-machinery.

S. No Name of the parameter Value Mass flow rate 5.73 kg/s Pressure ratio 5.4:1 Efficiency 82% Maximum impeller diameter 280 mm Maximum diffuser diameter 340 mm Rotational speed 38,000 rpm Inlet pressure 101,325 Pa Inlet temperature 288.15 K

Impeller was designed using guidelines from various sources and in specific from [6]. The number of impeller blade profiles was configured based upon a choice iterative method aiming for passage flow devoid of heavy separations, and it was streamlined and set at 19 blade profiles. A rotational speed of 38,000 rpm was set for the impeller.
