Alireza Ameli, Antti Uusitalo, Teemu Turunen-Saaresti, Jari Backman

14.09.2017 ORC2017 - alireza.ameli@lut.fi 2

Outline

3

Introduction

Numerical methods & studied case

Real Gas Properties (RGP)

Result - Performance

Result – Flow field

Extended studies

ORC2017 - alireza.ameli@lut.fi

4

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

ORC2017 - alireza.ameli@lut.fi

• Numerical simulations with ANSYS CFX 17.0

• Structured mesh by using Turbo Grid (about 1.4 million cells)

• 𝑘 − 𝜔 SST Turbulence model

• Sandia radial turbine (main)*

• Boundary conditions: 𝑝𝑡, 𝑇𝑡 & 𝑝𝑠 - 𝑝𝑡, 𝑇𝑡 & 𝑚 • Unsteady state simulation (Time Transformation)

5

* S. A. Wright, P. S. Pickard, M. E. Vernon, R. F. Radel and R. Fuller, "Description and Test Results from a Supercritical CO2 Brayton

Cycle Development Program," in 7th International Energy Conversion Engineering Conference, Denver, Colorado, 2-5 August, 2009.

ORC2017 - alireza.ameli@lut.fi

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

6

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

ORC2017 - alireza.ameli@lut.fi

7 ORC2017 - alireza.ameli@lut.fi

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

8

RGP 100

RGP 250

RGP500

ORC2017 - alireza.ameli@lut.fi

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

1- Specific entropy

2- Specific enthalpy

3- Speed of sound

4- Specific volume

5- Specific heat at constant pressure

6- Specific heat at constant volume

7- Dynamic viscosity

8- Thermal conductivity

9- Partial derivative of pressure with respect to specific volume at constant temperature.

RGP 100

RGP 250

RGP500

9

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

ORC2017 - alireza.ameli@lut.fi

10

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

0

200

400

600

800

1000

1200

1400

1600

1800

CP

U t

ime

se

co

nd

per

tim

e s

tep

Ideal RGP 100 RGP 250 RGP 500

ORC2017 - alireza.ameli@lut.fi

11

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000

2000000

CP

U t

ime

se

co

nd

per

roto

r ro

tati

on

Ideal RGP 100 RGP 250 RGP 500

ORC2017 - alireza.ameli@lut.fi

12

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

Ideal gas assumption Real gas assumption

ORC2017 - alireza.ameli@lut.fi

13

Undergoing researches:

• Design a centrifugal compressor with current and modified loss

models.

Sandia Supercritical CO2 Radial compressor

ORC2017 - alireza.ameli@lut.fi

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

14

40

45

50

55

60

65

70

75

80

85

90

0,037 0,04 0,043 0,046 0,049 0,052 0,055 0,058

Eff

icie

ncy (

%)

Flow coefficient

Experimental CFD 1D model

Introduction

Numerical methods &

studied case

Real Gas Properties

(RGP)

Result Performance

Result Flow fields

Extended studies

ORC2017 - alireza.ameli@lut.fi

15 ORC2017 - alireza.ameli@lut.fi