Speaker
Prof.
Parthasarathi Ghosh
(Cryogenic Engineering Centre, Indian Institute of Technology Kharagpur, India-721302)
Description
The demand for low temperature operations for liquefaction and refrigeration at cryogenic temperature, for air separation, gas purification, superconductivity etc has necessitated the need for improvement in turboexpander performance in terms of isentropic efficiency. The design of turboexpander for liquefaction systems is quite critical at low temperatures due to process conditions such as lower volumetric flow rate as compared to the high temperature turbines and thermo physical properties of fluids at low temperature. In order to evolve a design that yields better isentropic efficiency, it is imperative to understand the sources of inefficiency through investigation of flow physics in the turbine designed based on existing methodology.
The experimental techniques for the study of turbomachinery flows at cryogenic temperature are quite involved and expensive. Computational Fluid Dynamics (CFD) provides insight into these most complex turboexpander flow characteristics which includes secondary flows, boundary layer formation, separated flows, rotor stator interactions etc.
In the present work, 3D turbulent flow analysis of a cryogenic turboexpander for small scale air separation was performed using Ansys CFX. The turboexpander has been designed based on design methodologies proposed by Balje, Kun and Sentz and Hasselgruber. The different models adopted for the simulation such as that for turbulence and modelling technique for rotor have been discussed. The data obtained from simulations have been used to analyse the aerothermodynamic performance of the different components of the machine like nozzle, vaneless space, wheel and diffuser. Attempts have been made to identify the different sources of losses in these components.
Author
Mr
Rahul Verma
(Cryogenic Engineering Centre, Indian Institute of Technology Kharagpur, India-721302)
Co-authors
Mr
Ashish Alex Sam
(Cryogenic Engineering Centre, Indian Institute of Technology Kharagpur, India-721302)
Prof.
Parthasarathi Ghosh
(Cryogenic Engineering Centre, Indian Institute of Technology Kharagpur, India-721302)
