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Aerodynamic Loading distribution Effects on the Overall Performance of Ultra-High-Lift LP Turbine Cascades

Journal of Thermal Science 2014年第1期23卷 1-12页

作者： M.Berrino F.Satta d.simoni M.Ubaldi P.Zunino F.Bertini dIME Università degli Studi di Genova Via Montallegro 1I-16145 GenovaItaly Avio S.p.A. Professors I Maggio 56I-10040 Rivalta (TO) Italy

The present paper reports the results of an experimental investigation aimed at comparing aerodynamic perform- ance of three low-pressure turbine cascades for several Reynolds numbers under steady and unsteady inflows. This study is focused on finding design criteria useful to reduce both profile and secondary losses in the aero-engine LP turbine for the different flight conditions. The baseline blade cascade, characterized by a standard aerodynamic loading （Zw=1.03）, has been compared with two Ultra-High-Lift profiles with the same Zweifel number （Zw=1.3 for both cascades）, but different velocity peak positions, leading to front and mid-loaded blade cascade configurations. The aerodynamic flow fields downstream of the cascades have been experimentally in- vestigated for Reynolds numbers in the range 70000〈Re〈300000, where lower and upper limits are typical of cruise and take-off/landing conditions, respectively. The effects induced by the incoming wakes at the reduced frequency ./＋=0.62 on both profile and secondary flow losses for the three different cascade designs have been studied. Total pressure and velocity distributions have been measured by means of a miniaturized 5-hole probe in a tangential plane downstream of the cascade for both inflow conditions. The analysis of the results allows the evaluation of the aerodynamic performance of the blade cascades in terms of profile and secondary losses and the understanding of the effects of loading distribution and Zweifel number on secondary flows. When operating un- der unsteady inflow, contrarily to the steady case, the mid-loaded cascade has been found to be characterized by the lowest profile and secondary losses, making it the most attractive solution for the design of blades working in real conditions where unsteady inflow effects are present.

关键词： Low-Pressure Turbine Ultra-High-Lift Prof'des Profile Losses Secondary Losses Mid-Loaded Blade Cascades Aft-Loaded Blade Cascades.

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Experimental Investigation of Flow Instabilities in a Laminar Separation Bubble

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Journal of Thermal Science 2014年第3期23卷 203-214页

作者： simoni d. Ubaldi M. Zunino P. dIME-Università di GenovaVia Montallegro 1 I-16145 Genova Italy dIME-Università di Genova Via Montallegro 1 I-16145 Genova Italy

The present paper reports the results of a detailed experimental study aimed at investigating the dynamics of a laminar separation bubble, from the origin of separation up to the breakdown to turbulence of the large scale co- herent structures generated as a consequence of the Kelvin-Helmholtz instability process. Measurements have been performed along a fiat plate installed within a double contoured test section, designed to produce an adverse pressure gradient typical of Ultra-High-Lift turbine blade profiles, which induces the formation of a laminar separation bubble at low Reynolds number condition. Measurements have been carried out by means of comple- mentary techniques： hot-wire （HW） anemometry, Laser doppler Velocirnetry （LdV） and Particle Image Veloci- metry （PIV）. The high accuracy 2-dimensional LdV results allow investigating reverse flow magnitude and both Reynolds normal and shear stress distributions along the separated flow region, while the high frequency response of the HW anemometer allows analyzing the amplification process of flow oscillations induced by instability mechanisms. PIV results complement the flow field analysis providing information on the generation and evolu- tion of the large scale coherent structures shed as a consequence of the separated shear layer roll-up, through in- stantaneous velocity vector maps. The simultaneous analysis of the data obtained by means of the different meas- uring techniques allows an in depth view of the instability mechanisms involved in the transition/reattachrnent processes of the separated shear layer.

关键词： Ultra-High-Lift turbine profiles separated flow transition mode streaks Kelvin-Helmholtz instabil- ity linear stability theory

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Experimental Investigation of Separation and Transition Processes on a High-Lift Low-Pressure Turbine Profile Under Steady and Unsteady Inflow at Low Reynolds Number

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Journal of Thermal Science 2010年第1期19卷 26-33页

作者： Satta F simoni d Ubaldi M Zunino P Bertini F dIMSET-Università di Genova Via Montallegro 1I-16145 GenovaItaly Avio R&d V.I Maggio99 I-10040 Rivalta(TO)-Italy

The effects induced by the presence of incoming wakes on the boundary layer developing over a high-lift low-pressure turbine profile have been investigated in a linear cascade at *** tested Reynolds number is 70000,typical of the cruise operating *** results of the investigations performed under steady and unsteady inflow conditions are *** unsteady investigations have been performed at the reduced frequency of f+=0.62,representative of the real engine operating *** aerodynamic loadings as well as boundary layer velocity profiles have been measured to survey the separation and transition *** analysis has been also performed to better understand the phenomena associated with the transition process under steady *** the unsteady case,a phase-locked ensemble averaging technique has been employed to reconstruct the time-resolved boundary layer velocity distributions from the hot-wire instantaneous signal *** ensemble-averaging technique allowed a detailed analysis of the effects induced by incoming wakes-boundary layer interaction in separation ***-resolved results are presented in terms of mean velocity and unresolved unsteadiness time-space plots.

关键词： boundary layer separation boundary layer transition wake-boundary layer interaction high-liftprofile low-pressure turbine

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Free-stream Turbulence Effects on the Boundary Layer of a High-lift Low-Pressure-Turbine Blade

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Journal of Thermal Science 2016年第3期25卷 195-206页

作者： simoni d. Ubaldi M. Zunino p. Ampellio E. dIME-Universita di Genova Via MontaUegro 11-16145 GenovaItaly GE AvioAero S.p.A. V.I Maggio99 1-10040 Rivalta(TO)-Italy

The suction side boundary layer evolution of a high-lift low-pressure turbine cascade has been experimentally in- vestigated at low and high free-stream turbulence intensity conditions. Measurements have been carded out in order to analyze the boundary layer transition and separation processes at a low Reynolds nttmber, under both steady and unsteady inflows. Static pressure distributions along the blade surfaces as well as total pressure distri- butions in a downstream tangential plane have been measured to evaluate the overall aerodynamic efficiency of the blade for the different conditions. Particle. Image Velocimetry has been adopted to analyze the time-mean and time-varying velocity fields. The flow field has been surveyed in two orthogonal planes （a blade-to-blade plane and a wall-parallel one）. These measurements allow the identification of the Kelvin-Helmholtz large scale cohe- rent structures shed as a consequence of the boundary layer laminar separation under steady inflow, as well as the investigation of the three-dimensional effects induced by the intermittent passage of low and high speed streaks. A close inspection of the time-mean velocity profiles as well as of the boundary layer integral parameters helps to characterize the suction side boundary layer state, thus justifying the influence of free-stream turbulence intensity on the blade aerodynamic losses measured under steady and unsteady inflows.

关键词： profile losses high-lift profiles free-stream turbulence streaks unsteady flows.

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Profile and Secondary Flow Losses in a High-Lift LPT Blade Cascade at different Reynolds Numbers under Steady and Unsteady Inflow Conditions

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Journal of Thermal Science 2012年第6期21卷 483-491页

作者： Satta F. simoni d. Ubaldi M. Zunino P. Bertini F. dIMSET-Università di Genova Via Montallegro 1I-16145 GenovaItaly Avio S.p.A. Viale I Maggio 56I-10040 Rivalta(TO)-Italy

The aerodynamic flow field downstream of a Low-Pressure High-Lift(HL)turbine cascade has been experimentally investigated for different Reynolds numbers under both steady and unsteady inflows,in order to analyse the cascade performance under real engine operating *** Reynolds number has been varied in the range 100000d upper limits are typical of cruise and take-off/landing conditions,*** effects induced by the incoming wakes at the reduced frequency f+=0.62 on both profile and secondary flow losses have been *** pressure,velocity and secondary kinetic energy distributions at the downstream tangential plane have been measured by means of a miniaturized 5-hole *** quantities provide information on both blade wake and secondary flow structures(passage and horse-shoe vortices).The analysis of the results allows the evaluation of the aerodynamic performance of the HL front-loaded blade in terms of both profile and secondary losses.

关键词： profile losses secondary flow losses high-lift profdes unsteady inflow LPT blade.

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Turbine Blade Boundary Layer Separation Suppression via Synthetic Jet: an Experimental and Numerical Study

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Journal of Thermal Science 2012年第5期21卷 404-412页

作者： Bernardini C. Carnevale M. Manna M. Martelli F. simoni d. Zunino P. Università degli Studi di Firenze Firenze Italy Università degli Studi di Napoli Federico Ⅱ Napoli Italy Università degli Studi di Firenze FirenzeItaly Università degli Studi di Genova Genova Italy

The present paper focuses on the analysis of a synthetic jet device (with a zero net massflow rate) on a separated boundary layer. Separation has been obtained on a flat plate installed within a converging-diverging test section specifically designed to attain a local velocity distribution typical of a high-lift LPT blade. Both experimental and numerical investigations have been carried out. Unsteady RANS results have been compared with experiments in terms of time-averaged velocity and turbulence intensity distributions. Two different Reynolds number cases have been investigated, namely Re = 200,000 and Re = 70,000, which characterize low-pressure turbine operating conditions during take-off/landing and cruise. A range of synthetic jet aerodynamic parameters (Strouhal number and blowing ratio) has been tested in order to analyze the features of control-separated boundary layer interaction for the aforementioned Reynolds numbers.

关键词： Synthetic Jet Separated Flow Active Flow Control Unsteady Flow Ultra High Lift LPT.

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Ursodeoxycholic acid improves gastrointestinal motility defects in gallstone patients

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World Journal of Gastroenterology 2006年第33期12卷 5336-5343页

作者： A Colecchia G Mazzella L Sandri F Azzaroli M Magliuolo P simoni ML Bacchi-Reggiani E Roda d Festi department of Internal Medicine and Gastroenterology University of Bologna Bologna Italy department of Pharmaceutical Sciences University of Bologna Bologna Italy department of Cardiovascular diseases University of Bologna Bologna Italy

AIM: To simultaneously evaluate the presence of defects in gallbladder and gastric emptying, as well as in intestinal transit in gallstone patients (GS) and the effect of chronic ursodeoxycholic acid (UdCA) administration on these parameters and on serum bile acids and clinical outcome in GS and controls (CTR). METHOdS: After a standard liquid test meal, gallbla-dder and gastric emptying (by ultrasound), oroileal transit time (OITT) (by an immunoenzymatic technique) and serum bile acids (by HPLC) were evaluated before and after 3 mo of UdCA (12 mg/kg bw/d) or placebo administration in 10 symptomatic GS and 10 matched healthy CTR. RESULTS: OITT was longer in GS than in CTR (P dCA significantly reduced OITT in GS (P d longer gastric half-emptying time (t1/2) than CTR (P dCA, t1/2 significantly decreased (P dministration had no effect on gastric emptying and intestinal transit in both GS and CTR. CONCLUSION: The gallstone patient has simultaneous multiple impairments of gallbladder and gastric emptying, as well as of intestinal transit. UdCA administration restores these defects in GS, without any effect in CTR. These results confirm the pathogenetic role of gastrointestinal motility in gallstone disease and suggest an additional mechanism of action for UdCA in reducing bile cholesterol supersaturation.

关键词： Bile acids Biliary cholesterol deoxycholic acid Gallbladder emptying Gastric emptying Intestinaltransit Tauroursodeoxycholic acid

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Epidermal growth factor receptor pathway substrate 8 (Eps8) expression in maturing testis

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Asian Journal of Andrology 2004年第3期6卷 195-203页

作者： Alain Wunsch Kai Strothmann Manuela simoni Jorg Gromoll Eberhard Nieschlag C.Marc Luetjens Institute of Reproductive Medicine of the University D-48129 MunsterGermanyInstitute of Reproductive Medicine of the UniversityD-48129 MunsterGermanyInstitute of Reproductive Medicine of the UniversityD-48129 MunsterGermanyInstitute of Reproductive Medicine of the UniversityD-48129 MunsterGermanyInstitute of Reproductive Medicine of the UniversityD-48129 MunsterGermanyInstitute of Reproductive Medicine of the UniversityD-48129 MunsterGermany

Aim: Although epidermal growth factor receptors are expressed in the testes, whether they signal through epidermal growth factor receptor pathway substrate 8 (Eps8) is unknown. Here we evaluated the expression pattern of Eps8 in the maturing testis. Methods: The expression of Eps8 was analysed by Northern blotting, immunocy-tochemistry and Western blotting in primary Sertoli cell cultures and in testicular tissue of rodents. Results: Eps8 is specifically expressed in gonocytes, Leydig and Sertoli cells of the neonatal rats and in Leydig and Sertoli cells of the adult rats and mice. Although gonocytes express Eps8, no signal was found in prepubertal or mature spermatogonia and the expression level of Eps8 in Sertoli cells increases with age. No regulation of Eps8 expression in primary immature rat Sertoli cells by Follicle stimulating hormone (FSH) was detected by Western blotting. Conclusion: Eps8 seems to be involved in the growth factor-controlled regulation of cell proliferation and differentiation in the seminiferous epithelium. Eps8 is a possible marker for gonocytes and in Sertoli cells it could be involved in crosstalk with other growth factor pathways.

关键词： gene expression isoform Sertoli cell gonocyte

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Combined Experimental and Numerical Investigations on the Roughness Effects on the Aerodynamic Performances of LPT Blades

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Journal of Thermal Science 2016年第1期25卷 32-42页

作者： Marco Berrino Fabio Bigoni daniele simoni Matteo Giovannini Michele Marconcini Roberto Pacciani Francesco Bertini dIME-Universita di Genova Via Montallegro116145GenovaItaly dIEF-Universita di Firenze Via Santa Marta350139FirenzeItaly GE Avio R&d Via I Maggio9910140Rivalta(TO)Italy

The aerodynamic performance of a high-load low-pressure turbine blade cascade has been analyzed for three different distributed surface roughness levels(Ra) for steady and unsteady inflows. Results from CFd simulations and experiments are presented for two different Reynolds numbers(300000 and 70000 representative of take-off and cruise conditions, respectively) in order to evaluate the roughness effects for two typical operating conditions. Computational fluid dynamics has been used to support and interpret experimental results, analyzing in detail the flow field on the blade surface and evaluating the non-dimensional local roughness parameters, further contributing to understand how and where roughness have some influence on the aerodynamic performance of the blade. The total pressure distributions in the wake region have been measured by means of a five-hole miniaturized pressure probe for the different flow conditions, allowing the evaluation of profile losses and of their dependence on the surface finish, as well as a direct comparison with the simulations. Results reported in the paper clearly highlight that only at the highest Reynolds number tested(Re=300000) surface roughness have some influence on the blade performance, both for steady and unsteady incoming flows. In this flow condition profile losses grow as the surface roughness increases, while no appreciable variations have been found at the lowest Reynolds number. The boundary layer evolution and the wake structure have shown that this trend is due to a thickening of the suction side boundary layer associated to an anticipation of transition process. On the other side, no effects have been observed on the pressure side boundary layer.

关键词： low-pressure turbine high-load profile roughness unsteady inflow CFd

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Y-chromosomal microdeletions and partial deletions of the Azoospermia Factor c(AZFc)region in normozoospermic,severe oligozoospermic and azoospermic men in Sri Lanka

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Asian Journal of Andrology 2006年第1期8卷 39-44页

作者： L.Fernando J.Gromoll T.R.Weerasooriya E.Nieschlag M.simoni Institute of Reproductive Medicine of the University Münster University HospitalD-48129 MünsterGermany Reproductive Biology LaboratoryFaculty of MedicineKarapitiyaGalleSri Lanka Institute of Reproductive Medicine of the University Münster University HospitalD-48129 MünsterGermany Reproductive Biology Laboratory Faculty of MedicineKarapitiyaGalleSri Lanka

Aim： To assess for the first time the occurrence of Y chromosomal microdeletions and partial deletions of the Azoospermia Factor c （AZFc） region in Sri Lankan men and to correlate them with clinical parameters. Methods： In a retrospective study, we analyzed 96 infertile men （78 with non-obstructive azoospermia） and 87 controls with normal spermatogenesis. AZFa, AZFb, AZFc and partial deletions within the AZFc region were analyzed by multiplex polymerase chain reaction （PCR） according to established protocols. Results： No AZFa, AZFb or AZFc deletions were found in the control group. Seven patients in the group of infertile men were found to have deletions as following： one AZFa, two AZFc, two AZFbc and two AZFabc. The relative distribution of these patterns was significantly different compared with that found in the German population. Extension analysis confirmed that the deletions occurred according to the current pathogenic model, gr/gr deletions were found to be equally present both in the patients （n = 4） and in the control group （n = 4）. One b2/b3 deletion was found in the patient group. Conclusion： These results suggest that the frequency and pattern of microdeletions of the Y chromosome in Sri Lankan men are similar to those found in other populations and confirm that gr/gr deletions are not sufficient to cause spermatogenetic failure. （Asian J Androl 2006 Jan; 8： 39-44）

关键词： Y chromosome male infertility gr/gr b2/b3 microdeletion normozoospermia azoospermia factor c

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