High speed puncture impact studies of three low pressure styrene thermoplastic structural foam plaques

1983 ◽  
Vol 3 (1) ◽  
pp. 15-22 ◽  
Author(s):  
R. C. Progelhof ◽  
S. Kumar ◽  
J. L. Throne
Keyword(s):  
High Speed ◽  
Low Pressure ◽  
Structural Foam ◽  
Impact Studies

Highly Loaded Low-Pressure Turbine: Design, Numerical, and Experimental Analysis

2010 ◽  
Author(s):  
J. T. Schmitz ◽  
S. C. Morris ◽  
R. Ma ◽  
T. C. Corke ◽  
J. P. Clark ◽  
...  
Keyword(s):  
High Speed ◽  
Numerical Solutions ◽  
Pressure Ratio ◽  
Low Pressure ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Free Stream Turbulence ◽  
Low Pressure Turbine ◽  
The Mean ◽  
Highly Loaded

The performance and detailed flow physics of a highly loaded, transonic, low-pressure turbine stage has been investigated numerically and experimentally. The mean rotor Zweifel coefficient was 1.35, with dh/U2 = 2.8, and a total pressure ratio of 1.75. The aerodynamic design was based on recent developments in boundary layer transition modeling. Steady and unsteady numerical solutions were used to design the blade geometry as well as to predict the design and off-design performance. Measurements were acquired in a recently developed, high-speed, rotating turbine facility. The nozzle-vane only and full stage characteristics were measured with varied mass flow, Reynolds number, and free-stream turbulence. The efficiency calculated from torque at the design speed and pressure ratio of the turbine was found to be 90.6%. This compared favorably to the mean line target value of 90.5%. This paper will describe the measurements and numerical solutions in detail for both design and off-design conditions.

scholarly journals Phase-transformation-induced lubrication of earthquake sliding

2017 ◽  
Vol 375 (2103) ◽  
pp. 20160008 ◽  
Author(s):  
Harry W. Green
Keyword(s):  
Phase Transformation ◽  
Dry Friction ◽  
High Speed ◽  
Frictional Resistance ◽  
Low Pressure ◽  
Self Healing ◽  
Strength Recovery ◽  
Endothermic Reactions ◽  
Shear Heating ◽  
Fast Motion

Frictional failure is not possible at depth in Earth, hence earthquakes deeper than 30–50 km cannot initiate by overcoming dry friction. Moreover, the frequency distribution of earthquakes with depth is bimodal, suggesting another change of mechanism at about 350 km. Here I suggest that the change at 30–50 km is from overcoming dry friction to reduction of effective stress by dehydration embrittlement and that the change at 350 km is due to desiccation of slabs and initiation by phase-transformation-induced faulting. High-speed friction experiments at low pressure indicate that exceeding dry friction provokes shear heating that leads to endothermic reactions and pronounced weakening. Higher-pressure studies show nanocrystalline gouge accompanying dehydration and the highest pressure experiments initiate by exothermic polymorphic phase transformation. Here I discuss the characteristic nanostructures of experiments on high-speed friction and high-pressure faulting and show that all simulated earthquake systems yield very weak transformation-induced lubrication, most commonly nanometric gouge or melt. I also show that phase-transformation-induced faulting of olivine to spinel can propagate into material previously transformed to spinel, apparently by triggering melting analogous to high-speed friction studies at low pressure. These experiments taken as a whole suggest that earthquakes at all depths slide at low frictional resistance by a self-healing pulse mechanism with rapid strength recovery. This article is part of the themed issue ‘Faulting, friction and weakening: from slow to fast motion’.

scholarly journals Liquid Film Flow Generated by High-speed Droplet Impact in Low-pressure Environment

2015 ◽  
Vol 28 (5) ◽  
pp. 531-537
Author(s):  
Masaya KATO ◽  
Masao WATANABE ◽  
Kazumichi KOBAYASHI ◽  
Toshiyuki SANADA
Keyword(s):  
Liquid Film ◽  
High Speed ◽  
Film Flow ◽  
Low Pressure ◽  
Droplet Impact ◽  
Liquid Film Flow

The Effects of Inlet Boundary Layer Condition and Periodically Incoming Wakes on Secondary Flow in a Low Pressure Turbine Cascade

2020 ◽  
Author(s):  
Tobias Schubert ◽  
Silvio Chemnitz ◽  
Reinhard Niehuis
Keyword(s):  
Boundary Layer ◽  
Secondary Flow ◽  
High Speed ◽  
Low Pressure ◽  
Experimental Investigations ◽  
Turbine Cascade ◽  
Flow Conditions ◽  
Low Pressure Turbine ◽  
Speed Flow ◽  
Unsteady Inflow

Abstract A particular turbine cascade design is presented with the goal of providing a basis for high quality investigations of endwall flow at high-speed flow conditions and unsteady inflow. The key feature of the design is an integrated two-part flat plate serving as a cascade endwall at part-span, which enables a variation of the inlet endwall boundary layer conditions. The new design is applied to the T106A low pressure turbine cascade for endwall flow investigations in the High-Speed Cascade Wind Tunnel of the Institute of Jet Propulsion at the Bundeswehr University Munich. Measurements are conducted at realistic flow conditions (M2th = 0.59, Re2th = 2·105) in three cases of different endwall boundary layer conditions with and without periodically incoming wakes. The endwall boundary layer is characterized by 1D-CTA measurements upstream of the blade passage. Secondary flow is evaluated by Five-hole-probe measurements in the turbine exit flow. A strong similarity is found between the time-averaged effects of unsteady inflow conditions and the effects of changing inlet endwall boundary layer conditions regarding the attenuation of secondary flow. Furthermore, the experimental investigations show, that all design goals for the improved T106A cascade are met.

Experimental Study of the Low-Pressure Water Jet Assisted Laser Processing of W6Mo5Cr4V2 High-Speed Steel

Applied laser ◽  
2013 ◽  
Vol 33 (2) ◽  
pp. 181-185
Author(s):  
王金华 Wang Jinhua ◽  
袁根福 Yuan Genfu ◽  
逄志伟 Pang Zhiwei ◽  
陈春映 Chen Chunying
Keyword(s):  
Experimental Study ◽  
Laser Processing ◽  
High Speed ◽  
High Speed Steel ◽  
Low Pressure ◽  
Water Jet ◽  
Pressure Water

scholarly journals A Concept of Integration of a Vactrain Underground Station with the Solidarity Transport Hub Poland

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5737
Author(s):  
Olena Stryhunivska ◽  
Katarzyna Gdowska ◽  
Rafał Rumin
Keyword(s):  
High Speed ◽  
Low Pressure ◽  
Advanced Technology ◽  
Planning Stage ◽  
Safety Standards ◽  
Planning And Design ◽  
Railway Infrastructure ◽  
Critical Issues ◽  
High Speed Trains ◽  
Underground Station

This paper provides an analysis of a designed underground station infrastructure for vacuum tube high-speed trains for the planned mega transport hub in Poland. The potential of integrating the infrastructure of the station building with sealed low-pressure tubes system is analyzed. The Solidarity Transport Hub Poland is a planned mega hub to be located in Baranów Municipality, Poland, which is comprised of an airport, an airport city, a road, and railway infrastructure. It is to be integrated with the first route of vactrains in Poland. The aim of this paper is to design a hyperloop station building adequate for the advanced technology of low-pressure high-speed trains. Designing a hyperloop station is not trivial, due to technological aspects which have not been hitherto present in airport or railway planning and design, such as low-pressure zones or airlocks which determine possible passenger paths and evacuation roads. Both the mega airport and Polish hyperloop are in the planning stage, therefore, in this paper, available models and designs of the hyperloop station building and infrastructure are used in order to formulate recommendations for further development and identify critical issues related to the safety and reduction of passenger transit time. The main contribution of this paper is a model of the hyperloop station building which respects the principles of spatial planning and safety standards.

scholarly journals Characterization of Periodic Incoming Wakes in a Low-Pressure Turbine Cascade Test Section by Means of a Fast-Response Single Sensor Virtual Three-Hole Probe

2019 ◽  
Vol 4 (3) ◽  
pp. 26
Author(s):  
Julien Clinckemaillie ◽  
Tony Arts
Keyword(s):  
Total Pressure ◽  
High Speed ◽  
Control Volume ◽  
Low Pressure ◽  
Fast Response ◽  
Pressure Probe ◽  
Flow Angle ◽  
Low Pressure Turbine ◽  
Wide Range ◽  
Good Agreement

This paper aims at evaluating the characteristics of the wakes periodically shed by the rotating bars of a spoked-wheel type wake generator installed upstream of a high-speed low Reynolds linear low-pressure turbine blade cascade. Due to the very high bar passing frequency obtained with the rotating wake generator (fbar = 2.4−5.6 kHz), a fast-response pressure probe equipped with a single 350 mbar absolute Kulite sensor has been used. In order to measure the inlet flow angle fluctuations, an angular aerodynamic calibration of the probe allowed the use of the virtual three-hole mode; additionally, yielding yaw corrected periodic total pressure, static pressure and Mach number fluctuations. The results are presented for four bar passing frequencies (fbar = 2.4/3.2/4.6/5.6 kHz), each tested at three isentropic inlet Mach numbers M1,is = 0.26/0.34/0.41 and for Reynolds numbers varying between Re1,is = 40,000 and 58,000, thus covering a wide range of engine representative flow coefficients (ϕ = 0.44−1.60). The measured wake characteristics show fairly good agreement with the theory of fixed cylinders in a cross-flow and the evaluated total pressure losses and flow angle variations generated by the rotating bars show fairly good agreement with theoretical results obtained from a control volume analysis.

scholarly journals Ultra-high speed visualization of a flash-boiling jet in a low-pressure environment

2019 ◽  
Vol 110 ◽  
pp. 238-255 ◽  
Author(s):  
Tariq Alghamdi ◽  
Sigurdur T. Thoroddsen ◽  
J.F. Hernández-Sánchez
Keyword(s):  
High Speed ◽  
Low Pressure ◽  
Ultra High Speed ◽  
Flash Boiling

A Comparison of Turbulence Levels From Particle Image Velocimetry and Constant Temperature Anemometry Downstream of a Low-Pressure Turbine Cascade at High-Speed Flow Conditions

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Silvio Chemnitz ◽  
Reinhard Niehuis
Keyword(s):  
Particle Image Velocimetry ◽  
Constant Temperature ◽  
High Speed ◽  
Particle Image ◽  
Low Pressure ◽  
Operating Conditions ◽  
Stereoscopic Particle Image Velocimetry ◽  
Turbine Cascade ◽  
Low Pressure Turbine ◽  
Image Velocimetry

Abstract The development and verification of new turbulence models for Reynolds-averaged Navier–Stokes (RANS) equation-based numerical methods require reliable experimental data with a deep understanding of the underlying turbulence mechanisms. High accurate turbulence measurements are normally limited to simplified test cases under optimal experimental conditions. This work presents comprehensive three-dimensional data of turbulent flow quantities, comparing advanced constant temperature anemometry (CTA) and stereoscopic particle image velocimetry (PIV) methods under realistic test conditions. The experiments are conducted downstream of a linear, low-pressure turbine cascade at engine relevant high-speed operating conditions. The special combination of high subsonic Mach and low Reynolds number results in a low density test environment, challenging for all applied measurement techniques. Detailed discussions about influences affecting the measured result for each specific measuring technique are given. The presented time mean fields as well as total turbulence data demonstrate with an average deviation of ΔTu<0.4% and ΔC/Cref<0.9% an extraordinary good agreement between the results from the triple sensor hot-wire probe and the 2D3C-PIV setup. Most differences between PIV and CTA can be explained by the finite probe size and individual geometry.

Temperature Measurement System for Low Pressure Ratio Turbine Testing

2003 ◽  
Author(s):  
R. Va´zquez ◽  
J. M. Sa´nchez
Keyword(s):  
Temperature Measurement ◽  
Measurement System ◽  
High Speed ◽  
New Technologies ◽  
Pressure Ratio ◽  
Low Pressure ◽  
High Accuracy ◽  
Single Stage ◽  
Measurement Systems ◽  
Temperature Measurement System

In 1999, ITP (Industria de Turbopropulsores, S.A.) launched a wide on-going research program focusing on new technologies to provide significant improvements in Low Pressure Turbines cost and weight. As consequence of the new technologies the experience limits are exceeded and new unknown concepts, like high stage loading turbines, must be explored and then a wide experimental work is required for validation purposes. Cold flow single stage rigs in high-speed facilities were selected by ITP as main vehicle to carry out the experimental validation. Single stage Low Pressure Turbine rigs have low-pressure ratio and power consumption, therefore efficiency predictions based on temperature drop require high accuracy thermocouple measurement systems (precision uncertainties lower than ±50 mK), if small efficiency variations must be captured. In this paper, a detailed uncertainty analysis is introduced and a temperature measurement system that allows achieving such high measurement accuracy is evaluated and described. Type T thermocouples are proposed for use in the range 0°C to 80°C, which are individually calibrated. The procedure followed for this calibration is presented and how is possible to achieve a precision of 30 mK. It is also shown as conventional UTR based on metal plates can behave as good as thermal baths in terms of temperature uniformity and errors, with the adequate isolation and temperature reference calibration. The conventional data recording and voltage measurement systems are experimentally evaluated, and they are found as main source of temperature errors. Although following some recommendations the precision of those systems can be improved, it is experimentally probed and therefore suggested the use of high accuracy voltmeter with a commutation unit to reduce significantly the temperature uncertainty. Finally a miniature Kiel Shroud is proposed and aerodynamically characterised in a high-speed facility. Mach, Reynolds number, yaw, blockage and manufacturing tolerance impact on recovery factor can be inferred from those results.

Sign in / Sign up

Export Citation Format

Share Document