Simulation of near surge instabilities onset in a turbocharger compressor

Després, Guillaume; Boum, Ghislaine Ngo; Leboeuf, Francis; Chalet, David; Chessé, Pascal; Lefebvre, Alain

doi:10.1177/0957650913495537

Cited by 11 publications

(9 citation statements)

References 14 publications

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“…If the flow pushed downstream by the impeller does not have enough flow momentum to overcome the pressure gradient in the di↵user, the flow direction is reversed at the impeller discharge and a tip leakage over the compressor blades establishes. The occurrence of such a flow reversal during o↵-design operating conditions at the outer periphery of the impeller is in agreement with the observations by Despres et al [10] using numerical flow simulations to investigate a di↵erent geometry. The tip leakage recirculations are increased towards lower mass-flow rates and lead to a distorted swirling flow at the inlet of the compressor, which result in a reduced performance of the impeller.…”

Section: Resultssupporting

confidence: 90%

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Flow phenomena leading to surge in a centrifugal compressor

Semlitsch

Mihăescu

2016

Energy

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Surge is a global flow instability occurring in centrifugal compressors at low mass-flow rate operation. Due to its violent nature, it is the limiting factor for operability. To enhance the operating range, understanding of the flow instability inception when approaching surge is essential. Therefore, the flow evolution along a speed line is analysed by performing unsteady, three-dimensional flow simulations using a centrifugal compressor geometry with ported shroud. A stable operating condition, at high mass-flow rates, is compared to lower mass-flow rate operating conditions close to and at surge. The particularities of the flow-fields are analysed and described. A smooth flow-field is observed for the stable operating condition, whereas flow reversal manifesting as tip leakage at the outer periphery of the impeller occurs for all o↵-design operating conditions. The reversed flow exhibits swirling motion in the impeller rotation direction. This induces a globally swirling flow upstream of the impeller, which influences the flow incidence angles at the blades and hence, their e ciency. Proper orthogonal decomposition and dynamic mode decomposition have been performed to analyse the flow structures appearing with surge more thoroughly. For the lowest mass-flow rate operating condition, low frequency modes describing the filling and emptying processes during surge have been found.

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Section: Resultssupporting

confidence: 90%

“…Unsteady RANS formulations [10], Detached Eddy Simulation (DES) [11] and the Large Eddy Simulation (LES) approach [12] have been used to describe the unsteady flow-field at o↵-design operating conditions. Unsteady RANS resolves the integral scales in a turbulent flow-field while all smaller flow scales are modelled.…”

Section: Introductionmentioning

confidence: 99%

Flow phenomena leading to surge in a centrifugal compressor

Semlitsch

Mihăescu

2016

Energy

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“…Particularly, compressor speed plays a role in the onset of whoosh noise, as indicated by Evans and Ward [3]. In fact, Després et al [32] did not found any rotating stall at an operating point close to surge but at low compressor speed. Experimental inlet spectra at high frequency range ( Fig.…”

Section: Compressor Acoustic Spectramentioning

confidence: 93%

“…Stall is more intense at the suction side (SS) of the main blades, which indicates that splitter blades should be closer to main blade pressure side (PS) rather than being a midpitch distance. Després et al [32] also noted that passages corresponding to main blade PS deliver more flow than channels which are delimited by the splitter blade PS for a midpitch location of the splitter blades. Moreover, Jeon [36] noted that, in a centrifugal fan, splitter blades located near main blade PS produce less overall SPL than the same impeller with splitter placed at a different pitchwise position.…”

Section: Flow Field Investigationmentioning

confidence: 99%

Numerical and experimental analysis of automotive turbocharger compressor aeroacoustics at different operating conditions

Broatch

Galindo

Garcia

et al. 2016

International Journal of Heat and Fluid Flow

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Centrifugal compressor aeroacoustics are analyzed by means of a 3-dimensional CFD model. Three operating points at nominal compressor speed are simulated ranging from best efficiency point to near-surge conditions. Experimental measurements are obtained using a steady flow rig mounted on an anechoic chamber. URANS and DES predictions of compressor global variables and pressure spectra are compared against experimental measurements. Flow-induced noise increases as the operating point moves towards surge line. Stall at the suction side of the blades exists even for high mass flow conditions, causing a high frequency boundary layer oscillation. Low momentum cells rotating at the diffuser are found at points closer to surge, causing the so-called whoosh noise. Inducer rotating stall is also present at these conditions. Point closest to surge shows a rotating tornado-type vortex at the inducer, determining a moving low pressure region that increases low frequency noise content.

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“…The deviations in the spectra of the sensors forming duct arrays can be contributed to the three-dimensional effects caused by duct modes and the propagation of flow instability due to the operation of the compressor near surge. The deviation among the spectra of the inlet duct array is primarily due to duct modes as the flow instability is reported only to propagate few diameters upstream [33,41]. Furthermore, a similar pattern is observed in the inlet spectra at design operation conditions thereby implying this to be a feature dependent on geometry rather than the flow conditions.…”

Section: Ps Open Configurationmentioning

confidence: 70%

Acoustic characterisation of a small high-speed centrifugal compressor with casing treatment: An experimental study

Sharma

Broatch

García-Tíscar

et al. 2019

Aerospace Science and Technology

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With the advancements in manufacturing, materials and computational methods, turbomachinery designs have become more efficient providing higher specific power and reliability with lower weight and cost. The rotational speed of turbomachines has increased while the overall machine size has decreased for a similar power output leading to the pervasive presence of small, high-speed turbomachines, specifically centrifugal compressors in helicopters, unmanned aerial vehicles (UAVs), auxiliary power units (APUs), turbochargers and micro gas turbines. In addition to superior aerodynamic performance over a wide range, increased operating speeds have made the acoustic emissions of small centrifugal compressors a critical aspect of design. Therefore, this work presents an experimental campaign to characterise the acoustic behaviour of a compressor with an intent to quantify the dominant features of the flow-induced noise for design and near surge operating conditions. Furthermore, the campaign is extended to establish the impact of the ported shroud casing treatment and operating speed on the acoustic emission of the compressor. The induct noise measurement method is used in this work to quantify the noise generated in the compressor by measuring pressure fluctuations near the inducer and diffuser while the propagation of the generated noise to the ducts is computed from an array of piezoelectric sensors. Spectra at the design operating point are dominated by tonal noise while broadband noise content is the dominant feature of spectra for near surge operation. Although the ported shroud cavity does not significantly alter the overall noise levels of the compressor operating at design condition, it does seem to propagate tonal noise. For near surge operation, the casing treatment positively impacts the acoustic emission with a reduction of approximately 10 dB in the range up to the blade pass frequency. Furthermore, various broadband features are also observed to be alleviated by the casing treatment.

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Simulation of near surge instabilities onset in a turbocharger compressor

Abstract: International audienc

Cited by 11 publications

References 14 publications

Flow phenomena leading to surge in a centrifugal compressor

Flow phenomena leading to surge in a centrifugal compressor

Numerical and experimental analysis of automotive turbocharger compressor aeroacoustics at different operating conditions

Acoustic characterisation of a small high-speed centrifugal compressor with casing treatment: An experimental study

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