scholarly journals The Flow Visualization of Small-Scale Aircraft Engine Axial Flow Turbine Rotor using Numerical Technique

2019 ◽  
Vol 9 (4) ◽  
pp. 777-784 ◽  
Author(s):  
Varun Chivukula et al., Varun Chivukula et al., ◽  
Keyword(s):  
Flow Visualization ◽  
Numerical Technique ◽  
Axial Flow ◽  
Aircraft Engine ◽  
Turbine Rotor ◽  
Small Scale

Influence of Leading Edge Fillet and Nonaxisymmetric Contoured Endwall on Turbine NGV Exit Flow Structure and Interactions With the Rim Seal Flow

2013 ◽  
Author(s):  
Özhan H. Turgut ◽  
Cengiz Camcı
Keyword(s):  
Flow Structure ◽  
Total Pressure ◽  
Guide Vane ◽  
Axial Flow ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Constant Thickness ◽  
Computational Evaluation ◽  
Nozzle Guide

Three different ways are employed in the present paper to reduce the secondary flow related total pressure loss. These are nonaxisymmetric endwall contouring, leading edge (LE) fillet, and the combination of these two approaches. Experimental investigation and computational simulations are applied for the performance assessments. The experiments are carried out in the Axial Flow Turbine Research Facility (AFTRF) having a diameter of 91.66cm. The NGV exit flow structure was examined under the influence of a 29 bladed high pressure turbine rotor assembly operating at 1300 rpm. For the experimental measurement comparison, a reference Flat Insert endwall is installed in the nozzle guide vane (NGV) passage. It has a constant thickness with a cylindrical surface and is manufactured by a stereolithography (SLA) method. Four different LE fillets are designed, and they are attached to both cylindrical Flat Insert and the contoured endwall. Total pressure measurements are taken at rotor inlet plane with Kiel probe. The probe traversing is completed with one vane pitch and from 8% to 38% span. For one of the designs, area averaged loss is reduced by 15.06%. The simulation estimated this reduction as 7.11%. Computational evaluation is performed with the rotating domain and the rim seal flow between the NGV and the rotor blades. The most effective design reduced the mass averaged loss by 1.28% over the whole passage at the NGV exit.

Predictions of Endwall Losses and Secondary Flows in Axial Flow Turbine Cascades

1987 ◽  
Vol 109 (2) ◽  
pp. 229-236 ◽  
Author(s):  
O. P. Sharma ◽  
T. L. Butler
Keyword(s):  
Flow Visualization ◽  
Secondary Flow ◽  
Axial Flow ◽  
Secondary Flows ◽  
Integral Boundary ◽  
Realistic Interpretation ◽  
Proposed Model ◽  
Flow Theories ◽  
Semi Empirical ◽  
End Wall

This paper describes the development of a semi-empirical model for estimating end-wall losses. The model has been developed from improved understanding of complex endwall secondary flows, acquired through review of flow visualization and pressure loss data for axial flow turbomachine cascades. The flow visualization data together with detailed measurements of viscous flow development through cascades have permitted more realistic interpretation of the classical secondary flow theories for axial turbomachine cascades. The re-interpreted secondary flow theories together with integral boundary layer concepts are used to formulate a calculation procedure for predicting losses due to the endwall secondary flows. The proposed model is evaluated against data from published literature and improved agreement between the data and predictions is demonstrated.

Influence of Honeycomb Rubbing on the Labyrinth Seal Performance

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Daniel Frączek ◽  
Włodzimierz Wróblewski ◽  
Krzysztof Bochon
Keyword(s):  
Aircraft Engine ◽  
Labyrinth Seal ◽  
Turbine Rotor ◽  
Geometrical Model ◽  
Computational Effort ◽  
Radial Clearance ◽  
Leakage Flow ◽  
Leakage Flows ◽  
Full Structure ◽  
Sst Turbulence Model

The aircraft engine operates in various conditions. In consequence, the design of seals must take account of the seal clearance changes and the risk of rubbing. A small radial clearance of the rotor tip seal leads to the honeycomb rubbing in take-off conditions, and the leakage flow may increase in cruise conditions. The aim of this study is to compare two honeycomb seal configurations of the low-pressure gas turbine rotor. In the first configuration, the clearance is small and rubbing occurs. In the second,—the fins of the seal are shorter to eliminate rubbing. It is assumed that the real clearance in both configurations is the same. A study of the honeycomb geometrical model is performed to reduce the computational effort. The problem is investigated numerically using the RANS equations and the two-equation k–ω SST turbulence model. The honeycomb full structure is taken into consideration to show details of the fluid flow. Main parameters of the clearance and leakage flows are compared and discussed for the rotor different axial positions. An assessment of the leakage flow through the seal variants could support the design process.

1-D Model Analysis of Tesla Turbine for Small Scale Organic Rankine Cycle (ORC) System

2017 ◽  
Author(s):  
Jian Song ◽  
Chun-wei Gu
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Organic Rankine Cycle ◽  
Axial Flow ◽  
Rankine Cycle ◽  
Expansion Ratio ◽  
Working Fluid ◽  
Small Scale ◽  
Low Grade ◽  
D Model

Energy shortage and environmental deterioration are two crucial issues that the developing world has to face. In order to solve these problems, conversion of low grade energy is attracting broad attention. Among all of the existing technologies, Organic Rankine Cycle (ORC) has been proven to be one of the most effective methods for the utilization of low grade heat sources. Turbine is a key component in ORC system and it plays an important role in system performance. Traditional turbine expanders, the axial flow turbine and the radial inflow turbine are typically selected in large scale ORC systems. However, in small and micro scale systems, traditional turbine expanders are not suitable due to large flow loss and high rotation speed. In this case, Tesla turbine allows a low-cost and reliable design for the organic expander that could be an attractive option for small scale ORC systems. A 1-D model of Tesla turbine is presented in this paper, which mainly focuses on the flow characteristics and the momentum transfer. This study improves the 1-D model, taking the nozzle limit expansion ratio into consideration, which is related to the installation angle of the nozzle and the specific heat ratio of the working fluid. The improved model is used to analyze Tesla turbine performance and predict turbine efficiency. Thermodynamic analysis is conducted for a small scale ORC system. The simulation results reveal that the ORC system can generate a considerable net power output. Therefore, Tesla turbine can be regarded as a potential choice to be applied in small scale ORC systems.

Assessment of Tidal Current Resources: Case Studies of Estuarine and Coastal Sites

2007 ◽  
Vol 18 (2) ◽  
pp. 233-249
Author(s):  
Jack Hardisty
Keyword(s):  
Shallow Water ◽  
Accurate Determination ◽  
Axial Flow ◽  
Sensitivity Analyses ◽  
Energy Output ◽  
Small Scale ◽  
Stream Power ◽  
Industry Standards ◽  
Tidal Stream ◽  
Scale Design

The potential for tidal stream power in North Western European waters is large and a number of axial flow, vertical rotor and oscillating hydroplane schemes are approaching full scale design and construction. The accurate determination of the available or potential fluid power is being addressed by, in particular, the regulatory bodies as they move towards the establishment of industry standards and the identification and designation of licensing areas. A generic formulation is developed here which utilises Admiralty tidal diamond data and the arithmetic summation of harmonics due to the lunar semi-diurnal, the solar semi-diurnal and (for shallow water and estuarine sites) the lunar quarter diurnal components. Numerical and sensitivity analyses show that the long term potential power is sensitive to the amplitudes of the harmonics but insensitive to the frequencies and phase differences. The results are applied to estuarine sites off Immingham and at Hull Roads in the Humber and to a shallow water, coastal site off Weston-super-Mare in the Bristol Channel. The results indicate that the shore side energy output from a small scale, meso-generation, 100 m2 capture area device with 60% efficiency varies from about 600 MWha–1 in the Bristol Channel to about 900 MWha–1 in the Humber where the ebb dominated tide flows for longer durations and at slightly higher speeds.

Linear Deterministic Source Terms for Hot Streak Simulations

2000 ◽  
Author(s):  
Paul D. Orkwis ◽  
Mark G. Turner ◽  
John W. Barter
Keyword(s):  
Boundary Condition ◽  
High Pressure ◽  
Source Term ◽  
Aircraft Engine ◽  
Turbine Rotor ◽  
High Pressure Turbine ◽  
Order Of Accuracy ◽  
Time Average ◽  
Hot Streak ◽  
Unsteady Effects

Steady state surface rothalpy results obtained with a lumped deterministic source term are compared with results obtained from a traditional nonlinear inviscid unsteady solution for an aircraft engine first stage high-pressure turbine rotor configuration. Boundary condition/potential field effects and the order of accuracy of the available schemes are shown to have a significant effect on surface rothalpy results. However, the new technique demonstrates a significant potential for including unsteady effects in time average calculations with minimal computer effort.

Flow Visualization Study of Jet and Bucket Interactions in Traditional and Hooped Pelton Runner

2019 ◽  
Author(s):  
Gaurangkumar Chaudhari ◽  
Salim Channiwala ◽  
Samip Shah ◽  
Digvijay Kulshreshtha
Keyword(s):  
Flow Visualization ◽  
Flow Pattern ◽  
High Speed ◽  
Early Stage ◽  
Small Scale ◽  
High Speed Photography ◽  
Pelton Turbine ◽  
Single Jet ◽  
Absolute Frame ◽  
First Time

Abstract This paper aims to study the flow pattern in and around a bucket of a Traditional and a Hooped Pelton runner at single injector operation and illustrates different stages of jet interaction. High speed photography is used to study the flow pattern, keeping the camera in different positions relative to the jet and to the bucket. It is concluded from the results that the flow visualization study, provides exceptional observations with an absolute frame of reference to mark the bucket duty period of a single-jet Pelton runner. The small scale models display erosion damages at the bucket lips, this indicated that the high pressure occur in the early stage of interaction. This fact is substantiated by the present flow visualization studies for the first time. The uncertainty of the free surface outflow within the Pelton turbine bucket establishes good documentation. The results are helpful to know the interaction between the jet and bucket of Pelton turbine.

Part-Span Application of Sweep and Lean at Turbine Blade Tips: A Low Speed Experimental Cascade Study

2010 ◽  
Author(s):  
Bhaskar Roy ◽  
Anoop Prajapati
Keyword(s):  
Performance Improvement ◽  
Turbine Blade ◽  
Axial Flow ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Pressure Surface ◽  
Wall Boundary Layer ◽  
Performance Reduction ◽  
Application Potential ◽  
End Wall

This study is aimed at exploring the possibility of aerodynamic performance improvement by providing part-span forward sweep and lean near the tip regions of axial flow turbine rotor blades. Such aerodynamic benefits may have application potential in the uncooled LPT blades. The curved forward sweep and curved lean have been provided to 25% of the blade span near the tip in cascade, Three sets of cascades of the same turbine airfoil have been studied — (i) straight blades, (ii) part span swept blades and (iii) part span leaned blades. The cascade results show that swept blade gives a recovery of 20–25% loss in blade performance near the tip region at 0° and 10° incidences. The swept and leaned blades suppress the Cp perturbations (as seen in straight blades) at 0° and at 10° incidences, on the suction surfaces of turbine blade cascades. Comparatively the leaned blades show blade unloading, largely on the pressure surface, which leads to some performance reduction. The wake loss study shows reduction in wake losses for swept turbine blade at near tip region. The end-wall boundary layer measurements across the open tips demonstrate some aerodynamic improvement, near the tip regions, for parts-span swept and leaned blades.

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