Area-Schedule Based Design of High Pressure Recovery Radial Diffusion Systems

Gao, Ruhou; Spakovszky, Z. S.; Rusch, Dana; Hunziker, René

doi:10.1115/gt2016-57044

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…For the performance evaluation of the diffuser, the static pressure recovery coefficient C p and the total pressure loss coefficient C pt are defined as [22]:…”

Section: Main Aerodynamic Parameters For Optimization Designmentioning

confidence: 99%

Investigation of New Design Principles for the Centrifugal Compressor Vaned Diffusers

Sun

et al. 2022

International Journal of Aerospace Engineering

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Diffuser’s aerodynamic performance is crucial for the centrifugal compressors, while at present the universal principles for the optimization design of the vaned diffusers are still not available. In this paper, three vaned diffusers with different inlet Mach numbers were numerically studied in order to explore new design principles for the centrifugal compressor vaned diffusers. It proved that there are practical and effective design principles for the vaned diffuser optimizations, the performance of the vaned diffuser can be improved by carefully control of two aerodynamic parameter distributions: Tangential velocity (Vt) and Meridional velocity (Vm). The vaned diffusers with subsonic, transonic and supersonic inlet conditions were optimized with the new design principles, and the peak efficiencies were increased by 4.23%, 2.15% and 2.59%, respectively. The stage pressure ratios were increased by 3.36%, 1.39% and 6.49%, respectively, and their surge margins were also improved substantially. Finally, since the Vt and Vm could affect each other during the optimization process, an interactive optimization design procedure was also presented in this paper in order to accelerate the optimization process.

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“…For the performance evaluation of the diffuser, the static pressure recovery coefficient C p and the total pressure loss coefficient C pt are defined as [22]:…”

Section: Main Aerodynamic Parameters For Optimization Designmentioning

confidence: 99%

Investigation of New Design Principles for the Centrifugal Compressor Vaned Diffusers

Sun

et al. 2022

International Journal of Aerospace Engineering

View full text Add to dashboard Cite

show abstract

“…The rise in the static pressure in relation to the conversion of kinetic energy into enthalpy can be characterized in terms of dimensionless coefficients. The static pressure recovery (c p,R ) and total pressure loss (c p,T,L ) coefficients can be given as (GAO et al, 2017;AYDER et al, 1993;EYNON;WHITFIELD, 2000;BALONI et al, 2012;BALONI et al, 2015)…”

Section: Pressure Coefficientsmentioning

confidence: 99%

Topology optimization for 2D swirl flows with application in the design of a ventricular assist device.

Alonso¹

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Ventricular Assist Devices (VADs) substitute or temporarily assist the heart and blood circulation by means of a small-scale blood pump. Due to the operation with blood, their designs aim to minimize blood damage (hemolysis and thrombosis) and maximize the performance (i.e., more efficient pumping). For that, the topologies of the rotor and the volute play a major role. In this research, the rotor is based on the 2D swirl concept, which considers swirling axisymmetric flow, being represented mainly by the Tesla pump.In a Tesla pump, the boundary layer (viscous) effect pumps the fluid, which may lead to less blood damage than bladed pumps (pumping based on the variation of linear momentum). However, the obtained efficiency is normally low, which may be improved by using the topology optimization method. Therefore, in this research, the topology optimization method is implemented for the 2D swirl flow model, also considering a non-Newtonian model for blood (Carreau-Yasuda) and hemolysis/thrombosis models to quantify the blood damage. Furthermore, the 2D swirl flow topology optimization is extended to the Wray-Agarwal turbulence model (WA2018), which presents advantages from the simulation and topology optimization points-of-view. The solid material is modeled as a porous medium with permeability controlled by the topology optimization.The numerical implementation is performed mainly through the FEniCS platform, by using the dolfin-adjoint library for the automatically derived adjoint model, and also relying on the OpenFOAM ® software for considering higher-speed flows, turbulence and 3D simulations. For the optimization, the IPOPT and TOBS solvers are considered. The optimized designs are interpreted and fabricated through additive manufacturing, and then experimentally evaluated.

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The Role of Impeller Outflow Conditions on the Performance of Vaned Diffusers

Everitt

Spakovszky

Rusch

et al. 2017

Journal of Turbomachinery

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Highly-loaded impellers, typically used in turbocharger and gas turbine applications, exhaust an unsteady, transonic flow that is non-uniform across the span and pitch and swirling at angles approaching tangential. With the exception of the flow angle, conflicting data exist regarding whether these attributes have substantial influence on the performance of the downstream diffuser. This paper quantifies the relative importance of the flow angle, Mach number, non-uniformity and unsteadiness on diffuser performance, through diffuser experiments in a compressor stage and in a rotating swirling flow test rig. This is combined with steady and unsteady Reynolds-Averaged Navier Stokes computations. The test article is a pressure ratio 5 turbocharger compressor with an airfoil vaned diffuser. The swirling flow rig is able to generate rotor outflow conditions representative of the compressor except for the periodic pitchwise unsteadiness, and fits a 0.86 scale diffuser and volute. In both rigs, the time-mean impeller outflow is mapped across a diffuser pitch using miniaturized traversing probes developed for the purpose.Across approximately two-thirds of the stage operating range, diffuser performance is well correlated to the average impeller outflow angle when the metric used is effectiveness, which describes the pressure recovery obtained relative to the maximum possible given the average inflow angle, Mach number and the vane exit metal angle. Utilizing effectiveness captures density changes through the diffuser at higher Mach numbers; a 10% increase in pressure recovery is observed as the inlet Mach number is increased from 0.5 to 1. Further, effectiveness is shown to be largely independent of the timeaveraged spanwise and unsteady pitchwise non-uniformity from the rotor; this independence is reflective of the strong mixing processes that occur in the diffuser inlet region. The observed exception is for operating points with high timeaveraged vane incidence. Here, it is hypothesized that temporary excursions into high-loss flow regimes cause a nonlinear increase in loss as large unsteady angle variations pass by from the rotor.Given that straight-channel diffuser design charts typically used in preliminary radial vaned diffuser design capture neither streamtube area changes from impeller exit to the diffuser throat nor vane incidence effects, their utility is limited. An alternative approach, utilizing effectiveness and vane leading edge incidence, is proposed. INTRODUCTIONModern high pressure ratio centrifugal compressors typically utilize a high speed impeller with backswept blades and a vaned diffuser. As part of ongoing efforts for a systemwide reduction in weight, increase in efficiency and/or reduction of emissions, designers seek to improve the pressure ratio, operating range and efficiency of the centrifugal compressor, which is often limited by the diffuser. Despite the relative simplicity of its geometry, the flow in the diffuser is complex and there is no well-established, reliable approach to gui...

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Area-Schedule Based Design of High Pressure Recovery Radial Diffusion Systems

Cited by 4 publications

References 7 publications

Investigation of New Design Principles for the Centrifugal Compressor Vaned Diffusers

Investigation of New Design Principles for the Centrifugal Compressor Vaned Diffusers

Topology optimization for 2D swirl flows with application in the design of a ventricular assist device.

The Role of Impeller Outflow Conditions on the Performance of Vaned Diffusers

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