Aerodynamic Design and Assessment of a Compact, Single Stage Axial Fan for Low Noise Emission

2019 ◽  
Author(s):  
Daniel Kessler ◽  
Daniel Giesecke ◽  
Jens Friedrichs ◽  
Jörg Leuschner
Keyword(s):  
Axial Length ◽  
Static Pressure ◽  
Test Chamber ◽  
Low Noise ◽  
Single Stage ◽  
Test Facility ◽  
Axial Fan ◽  
Noise Emission ◽  
Cooling Systems ◽  
The Impact

Abstract Axial fans used in automotive and especially in locomotive cooling systems have to follow several, partially contrary specifications. In addition to geometrical and aerodynamic specifications, acoustic limits must be taken into account for new fan stage designs. Legislation will tweak axial fan requirements in the future further and further to lower their noise emission and maximize their efficiency. The main focus of this paper is to design and test a single stage axial fan for locomotive cooling systems with high aerodynamic efficiency and low noise emissions. The fan stage is designed to be installed in a so-called tower construction. The available construction space is limited. Therefore, special attention is paid to reduce the axial length. Extensive blade sweep and dihedral are implemented in the design process. The fan stage design is validated by experimental tests including aerodynamic and acoustic studies. During the aerodynamic studies, it was found that an often used approximation about the static pressure downstream the fan cannot be applied. Downstream the fan stage no further components are installed. Therefore, the static pressure at this position must be approximated. An alternative approach is developed using the results of additional studies including a downstream pipe and scaling factors. The results of the approach are plausible. The acoustic tests were carried out at a fan test facility at TU Braunschweig. To evaluate the impact of the halls acoustic repercussion on the test results, different tests were done. Additionally, another axial fan was tested which has been investigated a few years ago in an acoustic test chamber. The studies show the positive effect of the design methodology on aerodynamic and acoustic of the fan stage. All requirements were achieved as well as a reduction of the axial length of the fan stage.

scholarly journals DEUFRABASE: A Simple Tool for the Evaluation of the Noise Impact of Pavements in Typical Road Geometries

Environments ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 27 ◽  
Author(s):  
Michel Bérengier ◽  
Judicaël Picaut ◽  
Bettina Pahl ◽  
Denis Duhamel ◽  
Benoit Gauvreau ◽  
...  
Keyword(s):  
Traffic Noise ◽  
Emission Spectra ◽  
Low Noise ◽  
Noise Emission ◽  
Simple Method ◽  
Acceptable Error ◽  
The Road ◽  
Noise Impact ◽  
On The Road ◽  
The Impact

Traffic noise is considered by people as one of the most important sources of environmental discomfort. A way to limit the traffic noise is to reduce the noise emission, for example, by using specific low noise pavements, particularly in suburban areas. However, in real situations, it can be difficult to evaluate the impact of a given pavement, because it depends, for example, on the road geometry, the meteorological conditions, or the distance of the receiver position. Finally it can be difficult to select the most appropriate pavement for a given noise reduction objective. In this paper, a simple method is proposed to evaluate the noise impact of a pavement, in typical road geometries and environmental conditions. The proposed approach uses two databases, the first one based on measurements of emission spectra of road vehicles on several typical pavements, the second one made of pre-calculations of noise propagation for typical road configurations. Finally, the method is implemented in an interactive web tool, called DEUFRABASE, which allows one to obtain a fast estimation of the L Aeq (1 h or 24 h) and L den noise levels for various pavements and road configurations, as functions of the traffic flow and composition. By comparing the method with measurements, it is showed that the tool, although based on a restricted number of pavements and on several simplifications, can predict the noise impact of typical road configurations, with an acceptable error, most often less than 2 dB.

An Advanced Single-Stage Turbine Facility for Investigating Non-Axisymmetric Contoured Endwalls in the Presence of Purge Flow

2019 ◽  
Author(s):  
Robin R. Jones ◽  
Oliver J. Pountney ◽  
Bjorn L. Cleton ◽  
Liam E. Wood ◽  
B. Deneys J. Schreiner ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Static Pressure ◽  
Optical Measurement ◽  
Guide Vane ◽  
Single Stage ◽  
Test Facility ◽  
Pressure Distributions ◽  
Mainstream Flow ◽  
Purge Flow ◽  
Nozzle Guide

Abstract In modern gas turbines, endwall contouring (EWC) is employed to modify the static pressure field downstream of the vanes and minimise the growth of secondary flow structures developed in the blade passage. Purge flow (or egress) from the upstream rim-seal interferes with the mainstream flow, adding to the loss generated in the rotor. Despite this, EWC is typically designed without consideration of mainstream-egress interactions. The performance gains offered by EWC can be reduced, or in the limit eliminated, when purge air is considered. In addition, EWC can result in a reduction in sealing effectiveness across the rim seal. Consequently, industry is pursuing a combined design approach that encompasses the rim-seal, seal-clearance profile and EWC on the rotor endwall. This paper presents the design of, and preliminary results from a new single-stage axial turbine facility developed to investigate the fundamental fluid dynamics of egress-mainstream flow interactions. To the authors’ knowledge this is the only test facility in the world capable of investigating the interaction effects between cavity flows, rim seals and EWC. The design of optical measurement capabilities for future studies, employing volumetric velocimetry and planar laser induced fluorescence are also presented. The fluid-dynamically scaled rig operates at benign pressures and temperatures suited to these techniques and is modular. The facility enables expedient interchange of EWC (integrated into the rotor bling), blade-fillet and rim-seals geometries. The measurements presented in this paper include: gas concentration effectiveness and swirl measurements on the stator wall and in the wheel-space core; pressure distributions around the nozzle guide vanes at three different spanwise locations; pitchwise static pressure distributions downstream of the nozzle guide vane at four axial locations on the stator platform.

One Stage and Two Stage Vibration Isolators as Applied to High Speed Textile Spindles to Achieve Noise Reduction

1978 ◽  
Vol 100 (1) ◽  
pp. 33-40 ◽  
Author(s):  
L. W. Foster
Keyword(s):  
Low Noise ◽  
Single Stage ◽  
Sound Power ◽  
Octave Band ◽  
Noise Levels ◽  
Two Stage ◽  
Noise And Vibration ◽  
Vibration Isolators ◽  
One Stage ◽  
The Impact

The operation of ring spinning frames in textile mills can create spinning room noise levels of 90 to 95 dBA. The spindle bobbin mechanisms (generally 300 to 400 per machine) which are operated at spindle speeds of 6,000 to 14,000 rpm are major sources of noise in this type of machinery. The rotating unbalance force in the spindle-bobbin mechanism creates high frequency vibrations in the spindle blade and in the spindle bolster which contains the bearings on which the blade rotates. The vibrations generated by the spindle bobbin mechanism and the bearings are transmitted through the spindle bolster to the rail structure of the spinning frame where they cause sand energy to be radiated. This paper describes the use of two types of elastomeric vibration isolators located between the spindle bolster and the rail to achieve reductions of vibration and noise levels associated with the spindle-bobbin-rail subsystem of spinning frames. The two types of elastomeric isolators employed are: (1) a single-stage isolator where a bonded elastomeric mounting of annular design is placed between the bolster and the rail, and (2) a two-stage isolator which incorporates an annular intermediate mass element between two annular elastomeric sections that provide the interfaces to the spindle and to the rail. The two stage isolator is a novel design for rotating spindle type applications and employs the classical two stage isolator principle to achieve greater attenuation of vibrations. While it has been known for some time that single stage elastomeric isolators provide an effective means of reducing vibrations and noise in textile spinning and twisting machines, recent emphasis on reducing machine noise levels has motivated increased effort to better describe and apply elastomeric isolators. The two-stage isolator concept has been employed in an attempt to achieve higher operating speeds and, therefore, higher productivity while keeping noise levels within acceptable limits. In order to demonstrate the degrees of noise and vibration reductions that can be attained using the two types of isolators in comparison with the non-isolated or hard-mounted spindle, tests were performed using a single oil base type spinning spindle with a full bobbin. The spindle-bobbin mechanism was mounted to a representative rail by the three mounting methods described previously and operated at speeds of 11,000 rpm and 14,000 rpm in a reverberation room. Octave band sound power level measurements and one-tenth octave band sound pressure measurements were made to compare the performance of the mounting methods. These measurements were made using six microphones at different locations and sampling their output signals at a high rate over an extended interval of time. One-tenth octave horizontal and vertical rail acceleration responses were obtained concurrently with the noise responses. These noise and vibration responses are presented and discussed in the paper. The results show that the elastomeric isolators provide significant reductions in rail vibration response levels in the spindle bearing vibration frequency range of 500 to 2000 Hz. The corresponding overall sound power levels for the two operating speeds when using one stage isolators were 8 to 18 dBA below the hard-mounted spindle condition. When using the two-stage isolator, the overall sound power levels for the two operating speeds were 9 and 20 dBA below the hard mounted spindle condition. The results demonstrate the importance of properly designing the mounting to tune the system for low noise responses while minimizing the impact on other operatonal criteria such as spindle static deflection and dynamic motion. A discussion of the isolator design parameter trade-offs is presented along with comments regarding the limitations of the testing and the constraints involved in predicting the noise level reduction to be expected for a whole spinning frame.

An Advanced Single-Stage Turbine Facility for Investigating Nonaxisymmetric Contoured Endwalls in the Presence of Purge Flow

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Robin R. Jones ◽  
Oliver J. Pountney ◽  
Bjorn L. Cleton ◽  
Liam E. Wood ◽  
B. Deneys J. Schreiner ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Static Pressure ◽  
Optical Measurement ◽  
Single Stage ◽  
Test Facility ◽  
Pressure Distributions ◽  
Mainstream Flow ◽  
Planar Laser ◽  
Flow Interactions ◽  
Purge Flow

Abstract In modern gas turbines, endwall contouring (EWC) is employed to modify the static pressure field downstream of the vanes and minimize the growth of secondary flow structures developed in the blade passage. Purge flow (or egress) from the upstream rim-seal interferes with the mainstream flow, adding to the loss generated in the rotor. Despite this, EWC is typically designed without consideration of mainstream–egress interactions. The performance gains offered by EWC can be reduced, or in the limit eliminated, when purge air is considered. In addition, EWC can result in a reduction in sealing effectiveness across the rim seal. Consequently, industry is pursuing a combined design approach that encompasses the rim-seal, seal-clearance profile, and EWC on the rotor endwall. This paper presents the design of and preliminary results from a new single-stage axial turbine facility developed to investigate the fundamental fluid dynamics of egress–mainstream flow interactions. To the authors' knowledge, this is the only test facility in the world capable of investigating the interaction effects between cavity flows, rim seals, and EWC. The design of optical measurement capabilities for future studies, employing volumetric velocimetry (VV) and planar laser-induced fluorescence (PLIF), is also presented. The fluid-dynamically scaled rig operates at benign pressures and temperatures suited to these techniques and is modular. The facility enables expedient interchange of EWC (integrated into the rotor bling), blade-fillet and rim-seal geometries. The measurements presented in this paper include: gas concentration effectiveness and swirl measurements on the stator wall and in the wheel-space core; pressure distributions around the nozzle guide vanes (NGV) at three different spanwise locations; pitchwise static pressure distributions downstream of the NGV at four axial locations on the stator platform.

Instability Characteristic of a Single-Stage Centrifugal Compressor Exposed to Dry and Wet Gas

2012 ◽  
Author(s):  
Trond G. Grüner ◽  
Lars E. Bakken
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Pressure Sensors ◽  
Ambient Air ◽  
Single Stage ◽  
Performance Characteristics ◽  
Test Facility ◽  
Wet Gas ◽  
And Performance ◽  
The Impact

An experimental investigation was conducted to determine the instability and performance characteristics of a single-stage centrifugal compressor exposed to wet gas. The compressor was tested at different rotational speeds and low gas mass fractions (GMFs) in an open-loop test facility with ambient air and water. The stage consisted of a shrouded impeller with a vaneless diffuser surrounded by a symmetrical circular volute with increasing cross-sectional area. Liquid was uniformly injected into the impeller eye through multiple nozzles mounted in the inlet pipe. High-response dynamic pressure sensors flush-mounted in the diffuser were used to identify instability inception and evolution. Changes in the instability and pressure ratio characteristics at different GMFs and rotational speeds were revealed. Analysis with reference to dry gas was performed. Visual observation of the wet gas surge process at the inlet is described. Results and analysis obtained from the experimental investigation on wet gas instability are presented. The investigation contributed to knowledge concerning the impact of wet gas on the instability and performance characteristics.

Experimental performance evaluation of a 99.0 mm radial inflow nozzled turbine with different stator throat areas

1997 ◽  
Vol 211 (6) ◽  
pp. 477-488 ◽  
Author(s):  
S W T Spence ◽  
D W Artt
Keyword(s):  
Experimental Data ◽  
Performance Evaluation ◽  
Static Pressure ◽  
Turbine Rotor ◽  
Single Stage ◽  
Test Facility ◽  
Experimental Performance ◽  
Mass Flowrate ◽  
Radial Inflow Turbine

The performance of a single-stage, radial inflow turbine was measured with seven vaned stators of different throat areas. The turbine test facility is described and details of the turbine rotor and stator geometry are provided. Efficiency, mass flowrates and rotor static pressure ratios are presented for each turbine configuration at a range of speeds and pressure ratios. The experimental data clearly shows the turbine mass flowrate increasing approximately in proportion to the stator throat area, while the maximum attainable efficiency decreased as the stator throat area decreased.

Performance Enhancement of a Small Centrifugal Cooling Fan

2013 ◽  
Vol 284-287 ◽  
pp. 878-882 ◽  
Author(s):  
Sheam Chyun Lin ◽  
Cheng Ju Chang ◽  
Ming Yuan Hsieh
Keyword(s):  
Heat Sink ◽  
Static Pressure ◽  
Performance Enhancement ◽  
Test Chamber ◽  
Maximum Flow ◽  
Thermal Dissipation ◽  
Centrifugal Fan ◽  
Axial Fan ◽  
High System ◽  
Improved Design

Under the rapid enhancement of CPU performance, the thermal management on the CPU becomes a challenging task, especially for the industrial PC with a high system resistance. The traditional axial fan with heat sink assembly is not capable to solve this difficult thermal-dissipation problem. Thus, a combination of centrifugal fan and heat sink is utilized to solve this high system-resistance for a server. A centrifugal fan is utilized to offer extra static pressure for drawing the hot air inside this compact enclosure and discharging to the atmosphere. In this study, experimental measurement and numerical simulation are integrated to improve the aerodynamic performance of a blower (80x 80x15 mm3) by redesigning its housing and rotor. Also, fan performance and acoustic experiment are conducted in an AMCA 210-99 test chamber and a semi-anechoic chamber following CNS-8753 code for ensuring a reliable test platform. In conclusion, based on experimental and CFD outcomes, the maximum flow rate and the static pressure of the improved design alternative are successfully increased by 19.5% and 25.53%, respectively.

Warm Model Ice and Propeller Interaction, Capturing the Driving Mechanics?

2014 ◽  
Author(s):  
Gerco Hagesteijn ◽  
Joris Brouwer
Keyword(s):  
High Speed ◽  
Open Water ◽  
Video Camera ◽  
Low Noise ◽  
Noise Emission ◽  
Force Vector ◽  
High Speed Video Camera ◽  
Propeller Blades ◽  
Set Up ◽  
The Impact

In the drive to design robust and more efficient propellers, the need to understand propeller-ice interaction is increasing. Traditionally MARIN has built up this kind of propeller design knowledge by developing and testing large systematic propeller series, such as the classic Wageningen B-series and the recent C and D-series. With systematic variations of blade number, area, pitch and profiles it can be investigated how these parameters influence the design and how the most efficient designs for operation in open water and in ice can be reached. This is becoming especially important for the lower ice class propellers, which are rarely sailing in ice covered areas. Apart from this, these designs should be optimized for low noise emission as well, to ensure application in the sensitive Arctic environment. When both milling and crushing loads can be captured using a warm model ice, the testing of such a large systematic propeller series becomes possible without the use of an ice basin. In the present paper an evaluation is presented, showing the results of a first series of testing that was carried out with a warm model ice. The test set-up used is one that has also been used for the same kind of tests in a real ice basin. The warm model ice was designed to resemble the correct crushing strength at model scale. The warm ice samples are fed into the propeller, while at the same time the load on one of the propeller blades is recorded with a 6C-load transducer. At the same time the impact is recorded with a high speed video camera. To enable a detailed analysis, the force vector is plotted on the high speed recording. The force vector can be derived using a centre of pressure method. In this way an evaluation can be made if the captured phenomena are indeed similar to those that can be expected from real (model-)ice.

Blow-Down Valve Noise and Interactions With Downstream Orifice Plates

2003 ◽  
Author(s):  
Denis G. Karczub ◽  
Fred W. Catron ◽  
Allen C. Fagerlund
Keyword(s):  
Noise Exposure ◽  
Control Valve ◽  
Low Noise ◽  
Noise Levels ◽  
Exposure Limits ◽  
Blow Down ◽  
Gas Processing ◽  
The Impact ◽  
Acoustic Fatigue ◽  
Infrequent Event

In a blow-down situation as might occur at a natural gas processing facility, noise levels are very high and significantly exceed the noise levels one would normally associate with a control valve. As the blow-down operation is an infrequent event, this may be permissible but requires consideration of the duration of these high noise levels to ensure that occupational noise exposure limits and acoustic fatigue limits are not exceeded. Tests of noise levels due to an 8-inch control valve in a 12-inch pipeline under blow-down conditions are compared here with noise level predictions based on the IEC standard. Consideration is also given to the impact of placing an orifice plate downstream of the control valve as is often done to reduce pressure drop across the valve in the expectation that control valve noise levels will be reduced. Simple orifice plates often installed by plant operators to achieve this goal are shown to have an adverse impact, and it is shown that a multi-hole diffuser or low-noise control valve should instead be used.

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