Structural Integrity of Serrated Leading Edge Guide Vane Blades for Noise Reduction

2021 ◽  
Author(s):  
Cleopatra Cuciumita ◽  
Ning Qin ◽  
Felix Stanley ◽  
Shahrokh Shahpar
Keyword(s):  
Passive Control ◽  
Structural Integrity ◽  
Guide Vane ◽  
Wave Length ◽  
Leading Edge ◽  
Von Mises Stress ◽  
Original Position ◽  
Structural Behaviour ◽  
Guide Vanes ◽  
Von Mises

Abstract One of the major noise sources of high bypass ratios modern turbofan engines arises from the interaction between the turbulent rotor wake, the tip-leakage and the leading edge of the downstream outlet guide vanes. Recent research has confirmed that leading edge serrations are an effective passive control for reducing noise. However, for transferring serrated leading edges to modern, environmentally friendly aero engines, the bypass outlet guide vanes must fulfil both aerodynamic and structural requirements. The current study aims at characterizing the structural behaviour when adding serrations to the leading edge of bypass outlet guide vanes designed for a configuration without classical struts. It was found that the structural performances deteriorate with increasing number of serrations, directly related to the serrations wavelength, and with their amplitude. The buckling loading factor decreases and the total deformation increases constantly with the increase of both parameters. The presence of the troughs of the serrations introduce stress concentrators. For large enough values of either the wave length or amplitude of the serrations, the maximum von Mises stress increases significantly, and can as much as double in value. At the same time, the location of the maximum stress on the vane moves from its original position, on the leading edge of the casing fillet, to the troughs of the serrations.

scholarly journals Mechanical Strength Study of a Cranial Implant Using Computational Tools

2022 ◽  
Vol 12 (2) ◽  
pp. 878
Author(s):  
Pedro O. Santos ◽  
Gustavo P. Carmo ◽  
Ricardo J. Alves de Sousa ◽  
Fábio A. O. Fernandes ◽  
Mariusz Ptak
Keyword(s):  
Structural Integrity ◽  
Mechanical Performance ◽  
Skull Fracture ◽  
Human Head ◽  
Element Model ◽  
Von Mises Stress ◽  
Cranial Implant ◽  
Von Mises ◽  
Two Parameters ◽  
The Brain

The human head is sometimes subjected to impact loads that lead to skull fracture or other injuries that require the removal of part of the skull, which is called craniectomy. Consequently, the removed portion is replaced using autologous bone or alloplastic material. The aim of this work is to develop a cranial implant to fulfil a defect created on the skull and then study its mechanical performance by integrating it on a human head finite element model. The material chosen for the implant was PEEK, a thermoplastic polymer that has been recently used in cranioplasty. A6 numerical model head coupled with an implant was subjected to analysis to evaluate two parameters: the number of fixation screws that enhance the performance and ensure the structural integrity of the implant, and the implant’s capacity to protect the brain compared to the integral skull. The main findings point to the fact that, among all tested configurations of screws, the model with eight screws presents better performance when considering the von Mises stress field and the displacement field on the interface between the implant and the skull. Additionally, under the specific analyzed conditions, it is observable that the model with the implant offers more efficient brain protection when compared with the model with the integral skull.

Ice Crystal Icing Investigation on a Honeywell Uncertified Research Engine in an Altitude Simulation Icing Facility

2020 ◽  
Author(s):  
Ashlie B. Flegel
Keyword(s):  
Particle Size ◽  
Guide Vane ◽  
Leading Edge ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Ice Crystal ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
The Core ◽  
Break Up

Abstract A Honeywell Uncertified Research Engine was exposed to various ice crystal conditions in the NASA Glenn Propulsion Systems Laboratory. Simulations using NASA’s 1D Icing Risk Analysis tool were used to determine potential inlet conditions that could lead to ice crystal accretion along the inlet of the core flowpath and into the high pressure compressor. These conditions were simulated in the facility to develop baseline conditions. Parameters were then varied to move or change accretion characteristics. Data were acquired at altitudes varying from 5 kft to 45 kft, at nominal ice particle Median Volumetric Diameters from 20 μm to 100 μm, and total water contents of 1 g/m3 to 12 g/m3. Engine and flight parameters such as fan speed, Mach number, and inlet temperature were also varied. The engine was instrumented with total temperature and pressure probes. Static pressure taps were installed at the leading edge of the fan stator, front frame hub, the shroud of the inlet guide vane, and first two rotors. Metal temperatures were acquired for the inlet guide vane and vane stators 1–2. In-situ measurements of the particle size distribution were acquired three meters upstream of the engine forward fan flange and one meter downstream of the fan in the bypass in order to study particle break-up behavior. Cameras were installed in the engine to capture ice accretions at the leading edge of the fan stator, splitter lip, and inlet guide vane. Additional measurements acquired but not discussed in this paper include: high speed pressure transducers installed at the trailing edge of the first stage rotor and light extinction probes used to acquire particle concentrations at the fan exit stator plane and at the inlet to the core and bypass. The goal of this study was to understand the key parameters of accretion, acquire particle break-up data aft of the fan, and generate a unique icing dataset for model and tool development. The work described in this paper focuses on the effect of particle break-up. It was found that there was significant particle break-up downstream of the fan in the bypass, especially with larger initial particle sizes. The metal temperatures on the inlet guide vanes and stators show a temperature increase with increasing particle size. Accretion behavior observed was very similar at the fan stator and splitter lip across all test cases. However at the inlet guide vanes, the accretion decreased with increasing particle size.

Computation of the Temperature Distribution in Cooled Radial Inflow Turbine Guide Vanes

1977 ◽  
Author(s):  
W. Tabakoff ◽  
W. Hosny ◽  
A. Hamed
Keyword(s):  
Temperature Distribution ◽  
Film Cooling ◽  
Guide Vane ◽  
Numerical Technique ◽  
Leading Edge ◽  
Guide Vanes ◽  
Heat Transfer Augmentation ◽  
Critical Areas ◽  
Internally Cooled ◽  
Convection Cooling

A two-dimensional finite-difference numerical technique is presented to determine the temperature distribution of an internally-cooled blade of radial turbine guide vanes. A simple convection cooling is assumed inside the guide vane. Such an arrangement results in relatively small cooling effectiveness at the leading edge and at the trailing edge. Heat transfer augmentation in these critical areas may be achieved by using impingement jets and film cooling. A computer program is written in Fortran IV for IBM 370/165 computer.

scholarly journals Cyclic Thermal Shock Damage Behavior in CVI SiC/SiC High-Pressure Turbine Twin Guide Vanes

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6104
Author(s):  
Xiaochong Liu ◽  
Xiaojun Guo ◽  
Youliang Xu ◽  
Longbiao Li ◽  
Wang Zhu ◽  
...  
Keyword(s):  
High Pressure ◽  
Thermal Shock ◽  
Failure Modes ◽  
Guide Vane ◽  
Chemical Vapor ◽  
Leading Edge ◽  
Chemical Vapor Infiltration ◽  
Thermal Shock Test ◽  
High Pressure Turbine ◽  
Guide Vanes

In this paper, the SiC/SiC high-pressure turbine twin guide vanes were fabricated using the chemical vapor infiltration (CVI) method. Cyclic thermal shock tests at different target temperatures (i.e., 1400, 1450, and 1480 °C) in a gas environment were conducted to investigate the damage mechanisms and failure modes. During the thermal shock test, large spalling areas appeared on the leading edge and back region. After 400 thermal shock cycles, the spalling area of the coating at the basin and back region of the guide vane was more than 30%, and the whole guide vane turned gray, due to the formation of SiO2. When the thermal shock temperature increased from 1400 to 1450 and 1480 °C, the spalling area of the basin and the back region of the guide vane did not increase significantly, but the delamination occurred at the tenon, upper surface of the guide vane near the trailing edge of the guide vane. Through the X-ray Computed Tomography (XCT) analysis for the guide vanes before and after thermal shock, there was no obvious damage inside of guide vanes. The oxidation of SiC coating and the formation of SiO2 protects the internal fibers from oxidation and damage. Further investigation on the effect of thermal shock on the mechanical properties of SiC/SiC composites should be conducted in the future.

scholarly journals Multiaxial fatigue criteria applied to motor crankshaft in thermoelectric power plants

2019 ◽  
Vol 300 ◽  
pp. 04003
Author(s):  
Marcos Venicius S. Pereira ◽  
Fathi Aref Darwish ◽  
André Feiferis ◽  
Tiago Lima Castro
Keyword(s):  
Thermoelectric Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Fatigue Behavior ◽  
Multiaxial Fatigue ◽  
Stress Fields ◽  
Von Mises Stress ◽  
Thermoelectric Power Plants ◽  
Octahedral Shear Stress ◽  
Von Mises

Fatigue failures of motor crankshafts operating in thermoelectric power plants have recently been reported. Stress fields provided by finite element calculations at critical points of a crankshaft that failed in service are used to test the structural integrity of the component. Taking into account the fact that the stresses acting at a given point are most likely out of phase, multiaxial fatigue criteria based on the von Mises stress are considered to be most suitable for predicting the fatigue behavior of the crankshaft. Using the von Mises stress, it was also possible to apply octahedral shear stress-based criteria and the results obtained have indicated that the crankshaft made of DIN 34CrNiMo6 steel should not suffer fatigue failure under the action of the stress fields in question. However, such failures have been occurring and this apparent discrepancy is presented and briefly discussed in the present study.

Sensitivity of Multi-Stage Compressor Performance Assessment to Measurement Rake Positions

2020 ◽  
Author(s):  
M. Chilla ◽  
G. Pullan ◽  
G. Thorne
Keyword(s):  
Performance Assessment ◽  
Potential Field ◽  
Large Scale ◽  
Guide Vane ◽  
Leading Edge ◽  
Stagnation Pressure ◽  
Guide Vanes ◽  
Multi Stage ◽  
Flow Mechanisms ◽  
Compressor Performance

Abstract For an accurate performance assessment of a multi-stage compressor, the circumferentially non-uniform flow at the compressor exit needs to be understood and sampled in a way that minimizes uncertainties. To quantify the effect of the measurement rake positions in the exit duct on compressor performance a combined computational and experimental approach is used on a modern 4-stage compressor. The computational analysis is based on unsteady calculations of a 180-degree sector of the test compressor and experimental verification is provided by comparing to area-traverse data downstream of the outlet guide vanes. It is shown that the exit measurement rakes are subject to circumferential flow variations caused primarily by the combined effect of the potential field of the struts housed within the exit duct and the wakes originating from the outlet guide vanes. A circumferential camber pattern, applied to the outlet guide vanes, designed to shield the upstream compressor blade rows against the potential field of the exit struts, is found to reduce the amplitude of the circumferential variation in stagnation pressure and shift its circumferential phase. Recognizing that a smaller numerical model, consisting only of the last rotor, the outlet guide vanes and the exit struts, is sufficient to capture the relevant flow mechanisms, the circumferential variations in stagnation pressure and temperature at the rake position are quantified as a function of the exit capacity. The stagnation pressure and temperature uncertainty within a +/-2 deg circumferential range around the nominal rake position is found to be up to 2.25 times larger than the change of the nominal values over an 87.1–106.0% variation of the exit capacity. Three options to position the rakes to reduce the uncertainty in compressor efficiency are presented — moving the rake downstream as well as leaning and verniering the rakes over the outlet guide vane pitch. Moving the rake from the leading edge to the trailing edge plane of the exit struts reduced the efficiency uncertainty by 2.6%, while leaning and verniering the rakes reduced the efficiency uncertainty by 0.2% and 0.7% respectively. The knowledge gained from the large-scale, detailed CFD predictions can used to support future measurement campaigns.

Numerical Investigations of the Long Blade Performance Using RANS Solution and FEA Method Coupled With One-Way and Two-Way Fluid-Structure Interaction Models

2017 ◽  
Author(s):  
Minyan Yin ◽  
Jun Li ◽  
Liming Song ◽  
Zhenping Feng
Keyword(s):  
Rotor Blade ◽  
Mechanical Performance ◽  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Leading Edge ◽  
Von Mises Stress ◽  
Maximum Displacement ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Von Mises

The aerodynamic and mechanical performance of the last stage was numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) solution and Finite Element Analysis (FEA) coupled with the one-way and two-way fluid-structure interaction models in this work. The part-span damping snubber and tip damping shroud of the rotor blade and aerodynamic pressure on rotor blade mechanical performance was considered in the one-way model. The two-way fluid-structure interaction model coupled with the mesh deformation technology was conducted to analyze the aerodynamic and mechanical performance of the last stage rotor blade. One-way fluid-structure interaction model numerical results show that the location of nodal maximum displacement moves from leading edge of 85% blade span to the trailing edge of 85% blade span. The position of nodal maximum Von Mises stress is still located at the first tooth upper surface near the leading edge at the blade root of pressure side. The two-way fluid-structure interaction model results show that the variation of static pressure distribution on long blade surface is mostly concentrated at upper region, absolute outflow angle of long blade between the 40% span and 95% span reduces, the location of nodal maximum displacement appears at the trailing edge of 85% blade span. Furthermore, the position of nodal maximum Von Mises stress remains the same and the value decreases compared to the oneway fluid-structure model results.

scholarly journals Structural analysis of deep soil loosening machine MAS-65

2019 ◽  
Vol 112 ◽  
pp. 03034 ◽  
Author(s):  
Mihai Gabriel Matache ◽  
Remus Marius Oprescu ◽  
Dragos Nicolae Dumitru ◽  
Gabriel Valentin Gheorghe ◽  
Dan Cujbescu ◽  
...  
Keyword(s):  
Structural Analysis ◽  
3D Model ◽  
Structural Integrity ◽  
Field Tests ◽  
Von Mises Stress ◽  
Strain Gages ◽  
Structural Failure ◽  
Deep Soil ◽  
Distribution Maps ◽  
Von Mises

Deep soil loosening machine MAS 65 is destined to work soil at depths exceeding 45 cm, thus the machine’s frame is subjected to loads which could affect its structural integrity. Within this paper a static structural analysis was performed on the machine’s 3D model using finite element method and strain and stress distribution maps were created. Using the Von Mises stress map there were identified several critical points which could fail during normal exploitation conditions and which should be monitored by strain gages during field tests in order to prevent structural failure.

An Analytical Study of the Structural Integrity of an LPG Storage Tank under Wind Load

2015 ◽  
Vol 741 ◽  
pp. 115-118 ◽  
Author(s):  
Bong Kwan Park ◽  
Jae Min Kim ◽  
Chang Min Keum ◽  
C. Kim ◽  
Heon Oh Choi
Keyword(s):  
Storage Tank ◽  
Structural Integrity ◽  
Element Model ◽  
Wind Load ◽  
Von Mises Stress ◽  
Shell Elements ◽  
Analytical Technique ◽  
Von Mises ◽  
Design Factors ◽  
Important Design

Since the wall thicknesses of most large LPG storage tanks are thin while their diameters are large, their structural integrity is one of the most important design factors. The tanks are mainly located near the waterfront for efficient transport and accessibility. This leads to exposure to wind loads, which should be considered in the design of the tanks. This paper describes an analytical technique for determining the structural integrity of a 45m diameter-LPG storage tank in the case of a wind load based on API 620 code. A finite element model for the tank was made using shell elements and analyzed under 50 m/s wind. The calculated maximum von-Mises stress was 103 MPa whereas the yield strength of tank’s material is 222 MPa. This result shows that the structural integrity of the tank is assured.

scholarly journals Streamlining Metal Poles

2000 ◽  
Vol 122 (04) ◽  
pp. 68-70
Author(s):  
Ioan Giosan ◽  
Ted Brockman
Keyword(s):  
Transmission Lines ◽  
Structural Integrity ◽  
Base Plate ◽  
Von Mises Stress ◽  
Roll Forming ◽  
Forming Process ◽  
Pole Type ◽  
Von Mises ◽  
The Impact ◽  
Stress Analyses

This article discusses that an engineering firm is using software to ensure the structural integrity of all types of pole designs. West Coast Engineering (WCE) Group in Delta, British Columbia, Canada, performed several linear stress analyses using software to optimize the insulator bracket, which supports the transmission lines on the tangent poles. Physical testing was used to verify the accuracy of the analysis results. WCE began the structural analyses by analyzing the shafts of each pole type under ultimate loading, which was determined by Ian Hayward International using standard industry calculations. WCE performed linear static stress analyses on the models and evaluated the von Mises stress criteria for ductile materials to assess the stress results. With the pole shaft and base plate structures verified, engineers focused the next analysis on the insulator brackets of the tangent structure to optimize the load bearing capability and material thickness. With the predictable loading capacity requirements confirmed for the designs, WCE expanded the study to include a simulation of the impact loading that can result from a head-on vehicle collision. WCE is continuing the use of Algor software in the design of poles and in the development of new pole manufacturing equipment. Currently, the company is using it to simulate and optimize a roll forming process.

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