Study of Unsteady Performance of a Twin-Entry Mixed Flow Turbine

Author(s):  
Bijie Yang ◽  
Ricardo Martinez-Botas

Abstract 1D modelling is crucial for turbomachinery unsteady performance prediction and system response assessment. The purpose of the paper is to describe a newly developed 1D modelling (TURBODYNA) for turbomachinery. Different from classic 1D modelling, in TURBODYNA, rotor has been meshed and its unsteadiness due to flow field time scale is considered. Instead of direct using of performances maps, source terms are added in Euler equation set to simulate the rotor. By comparing 1D modelling with 3D CFD results, It shows that rotor unsteadiness is indispensable for a better prediction. In addition, different variables response to pulse differently. In the rotor, mass flow is close to quasi-steady while entropy is significantly unsteady. TURBODYNA can capture these features correctly and provide an accurate prediction on pressure wave transportation.


2016 ◽  
Vol 57 (2) ◽  
pp. 300-307
Author(s):  
M. M. Bencherif ◽  
M. K. Hamidou ◽  
M. Hamel ◽  
M. Abidat

2019 ◽  
Vol 95 ◽  
pp. 105485 ◽  
Author(s):  
Yingxian Xue ◽  
Mingyang Yang ◽  
Ricardo F. Martinez-Botas ◽  
Bijie Yang ◽  
Kangyao Deng

2002 ◽  
Vol 3 (3) ◽  
pp. 127-138 ◽  
Author(s):  
N Karamanis ◽  
R. F. Martinez-Botas

Turbochargers are finding increasing application to automotive diesel engines as cost effective means for improving their power output and efficiency, and reducing exhaust emissions; these requirements have led to the need for highly loaded turbocharger turbines. A mixed-flow turbine is capable of achieving its peak isen-tropic efficiency at reduced velocity ratios compared to a typical radial inflow turbine; it is therefore possible to improve the turbocharger/engine matching. These turbines differ from the commonly used radial turbines in that the flow approaches the rotor in the non-radial direction; in the extreme a mixed-flow turbine would become an axial machine. The steady and unsteady performances of a mixed-flow turbocharger turbine with a constant blade inlet angle have been investigated. The steady flow results indicated that the mixed-flow turbine obtains a peak efficiency (total-to-static) of 75 per cent at a velocity ratio of 0.61, compared with that of a typical radial-inflow turbine which peaks at a velocity ratio of 0.7. The performance and flow characteristics were found to deviate significantly from the equivalent steady state values commonly used in turbocharger turbine design.


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