Experimental Investigation of Ambient Wind Influence on the Performance of Axial Fans

2014 ◽  
Author(s):  
Till Heinemann ◽  
Stefan Becker
Keyword(s):  
Wind Tunnel ◽  
Operating Mode ◽  
Positive Influence ◽  
Test Rig ◽  
Axial Fan ◽  
Axial Fans ◽  
Wind Velocities ◽  
Wind Influence ◽  
Water Scarce ◽  
The University

The EU-funded MACCSol project is developing a new modular air-cooled condenser design for power plant applications in water scarce regions. In that scope, this work is to examine the influence ambient winds may have on an axial ventilator’s performance. An axial fan test rig was built inside a wind tunnel environment at the University of Erlangen to realize different wind velocities and angles. Total fan pressure was captured using an array of 81 Kiel probes. The validity of the test rig adaptations to the wind tunnel restrictions was shown in comparison to results from ISO 5801 standard fan test rigs. Two different fan geometries were examined in their characteristic fan curves’ reactions to wind influence at the free fan inlet. The two fans’ characteristic curves showed effects differing in magnitude, but similar in their tendency. While frontal winds tended to improve fan performance, cross winds reduced it. In reverse operating mode, the effect of wind at the fan outlet demonstrated little but positive influence on the fan curve. In order to reduce negative cross wind influence at the fan inlet, different conical and cylindrical inlet extensions were tested. Short conical shrouds performed best.

Cross Wind Influence on Noise Emission and Computed Vibrational Noise of an Axial Fan

2015 ◽  
Author(s):  
Till Heinemann ◽  
Sven Münsterjohann ◽  
Florian Zenger ◽  
Stefan Becker
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Laser Scanning ◽  
Sound Pressure ◽  
Cross Flow ◽  
Test Rig ◽  
Axial Fan ◽  
Noise Emission ◽  
Axial Fans ◽  
Operating Points

The total noise emissions of two commercial axial fans were measured in a semi-anechoic fan test rig in comparison. The total sound pressure levels and the respective spectra were found to change with the fans’ operating points. Increasing fan flow rates lowered the total acoustic pressure, with a broadband shift towards higher frequencies, keeping perceived (A-weighted) sound pressure levels approximately constant over a wide range of operating points. In a second step, Laser Scanning Vibrometry measurements of the fan blades’ axial motion were conducted in comparison inside a wind tunnel fan test rig. Rotating blade surface vibration data was used as sole input to a Ffowcs Williams and Hawkings algorithm, to estimate noise emission from vibration. The computed noise from surface vibration was found to be hardly affected by the change of fan flow rate. In the application of an axial fan subject to natural wind or induced cross flow at its inlet, the flow field and possible noise emission of the fan changes. Microphone measurements of the cross flow influence inside a semi-anechoic wind tunnel revealed increasing broadband noise with ambient flow field velocity, and an amplification of the sound at the blade passing frequency harmonics. Similar excitations of the blade passing frequency harmonics under cross flow influence were also found in sound pressure spectra computations based on the Laser Scanning Vibrometry measurement data captured in the wind tunnel fan test rig. Blade vibration is considered to contribute to the low frequency tonal noise emission of axial fans operating under cross flow conditions.

scholarly journals Low-pressure reversible axial fan designed with different specific work of elementary stages

2012 ◽  
Vol 16 (suppl. 2) ◽  
pp. 605-615 ◽  
Author(s):  
Bozidar Bogdanovic ◽  
Zivan Spasic ◽  
Jasmina Bogdanovic-Jovanovic
Keyword(s):  
Suction Side ◽  
Low Pressure ◽  
Standard Test ◽  
Specific Work ◽  
Spatial Curvature ◽  
Operating Characteristics ◽  
Test Rig ◽  
Axial Fan ◽  
Air Intake ◽  
Axial Fans

Low-pressure axial fan impellers designed according to the principle of equal specific work of all elementary stages have blades whose profile near the fan hub is under a significantly larger inclination angle than at the impeller periphery. In order to minimize the spatial curvature of the fan blades and the fan hub length, impeller blades of low-pressure axial fans can be designed with different specific work of elementary stages, so that the specific work of elementary stages is smaller at the hub than at the periphery. This paper presents the operating characteristics of a low-pressure reversible axial fan with straight blade profiles, designed with different specific work of elementary stages. The fan was tested on a standard test rig, with air intake loading on the suction side of the fan.

scholarly journals COMPARISON OF AXIAL FAN ROTOR EXPERIMENTAL DATA WITH CFD SIMULATION

2016 ◽  
Vol 56 (1) ◽  
pp. 62 ◽  
Author(s):  
Aleš Prachař
Keyword(s):  
Experimental Data ◽  
Boundary Conditions ◽  
Cfd Simulation ◽  
Free Stream ◽  
Calculated Data ◽  
Experimental Simulation ◽  
Test Rig ◽  
Axial Fan ◽  
Axial Fans ◽  
Adequate Agreement

Data obtained from an experimental simulation on a new test rig for axial fans are compared to a CFD simulation. The Edge solver is used and the development needed for the simulation (boundary conditions, free stream consistency) is described. Adequate agreement between the measured and calculated data is observed.

السعادة في العمل ودورها في تعزيز الثقة التنظيمية بحث استطلاعي لآراء العاملين في جامعة الفلوجة.

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
ياسر خلف
Keyword(s):  
Negative Impact ◽  
Research Problem ◽  
Theoretical Framework ◽  
Positive Influence ◽  
Positive Change ◽  
Research Topic ◽  
Senior Management ◽  
University Employees ◽  
The University ◽  
The Relationship

The study aimed to clarify the role that happiness plays in the workplace represented by (positive influence, negative impact, and achievement) in enhancing organizational confidence among university employees represented in (confidence in senior management, trust in supervisors, trust in co-workers) as the research problem raised many questions It dealt with the nature of the relationship between the research variables and in light of these questions, two main hypotheses were formulated that reflect the correlation and influence relationships between the research variables, and in light of them, the hypothesis plan for the study was developed that reflects this. The data were analyzed and hypotheses were tested, as the research reached a set of conclusions, the most important of which is that there is a relationship between happiness in the workplace and organizational confidence. The research also recommended several recommendations, the most important of which is the necessity of continuing interest of the University of Fallujah to bring about positive change by understanding workers for work and the duties assigned to them. Completing the theoretical framework vocabulary on foreign sources, references, and literature related to the research topic,

scholarly journals A Simulation Study of Helicopter Ship Landing Procedures Incorporating Measured Flow-Field Data

2005 ◽  
Vol 219 (5) ◽  
pp. 411-427 ◽  
Author(s):  
D G Thomson ◽  
F Coton ◽  
R Galbraith
Keyword(s):  
Wind Tunnel ◽  
Wind Loading ◽  
Atmospheric Conditions ◽  
Wind Tunnel Tests ◽  
Inverse Simulation ◽  
Ship Model ◽  
Measured Flow ◽  
Wind Profiles ◽  
The University ◽  
Flight Deck

The aim of this article is to investigate the use of inverse simulation to help identify those regions of a ship's flight deck which provide the safest locations for landing a rotorcraft in various atmospheric conditions. This requires appropriate information on the wind loading conditions around a ship deck and superstructure, and for the current work, these data were obtained from wind tunnel tests of a ship model representative of a typical helicopter carrier/assault ship. A series of wind tunnel tests were carried out on the model in the University of Glasgow's 2.65 × 2.04 m wind tunnel and three-axis measurements of wind speed were made at various locations on the ship deck. Measurements were made at four locations on the flight deck at three different heights. The choice of these locations was made on the basis of preliminary flow visualization tests which highlighted the areas where the most severe wind effects were most likely to occur. In addition, for the case where the wind was from 30° to starboard, measurements were made at three further locations to assess the extent of the wake of the superstructure. The generated wind profiles can then be imposed on the inverse simulation, allowing study of the vehicle and pilot response during a typical landing manoeuvre in these conditions. The power of the inverse simulation for this application is demonstrated by a series of simulations performed using configurational data representing two aircraft types, a Westland Lynx and a transport helicopter flying an approach and landing manoeuvre with the worst atmospheric conditions applied. It is shown from the results that attempting to land in the area aft of the superstructure in a 30° crosswind might lead to problems for the transport configuration due to upgusts in this area. Attempting to perform the landing manoeuvre in an aggressive manner is also shown to lead to diminished control margin in higher winds.

Aeroacoustic Optimization of a Pressure-Side Strut Configuration for Subsonic Axial Fans Using Statistical-Empirical Modelling

2018 ◽  
Author(s):  
Igor Neifach ◽  
Gi-Don Na ◽  
Frank Kameier ◽  
Nils Springer ◽  
Marco Wichers
Keyword(s):  
Residential Buildings ◽  
Statistical Design ◽  
Axial Fan ◽  
Noise Emission ◽  
Public Places ◽  
Empirical Modelling ◽  
Passive Construction ◽  
Cooling Fan ◽  
Rotor Stator Interaction ◽  
Axial Fans

This paper deals with the reduction of aerodynamically generated noise in passenger car Cooling-Fan-Modules (CFM), caused by the interaction between the impeller and the downstream-located strut configuration of the axial fan. Even after the car engine is switched off, the fan remains active, as long as cooling is required for certain vehicle components. Especially after a car has been parked in closed parking areas, in close proximity to residential buildings or public places, the noise emission can be a problem. This issue is addressed by dampening the rotor-stator-interaction through passive construction measures. In order to ensure optimal noise reduction, 8 critical design features of the struts are identified and investigated using statistical design of experiment methods (DoE). Based on the results, dedicated insights about the effects of concrete strut features on significant regions of the acoustic fan spectrum are obtained. Furthermore, an optimized strut configuration is derived and metrologically validated using a polyoptimization method. Compared to a current serial baseline configuration, a reduction of the overall sound pressure level by 2.6 dB(A), as well as a reduction of the blade passage frequency tone by 17.6 dB(A) is achieved.

scholarly journals Experimental investigation of an annular diffuser for axial fans at different inflow profiles

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 553-564
Author(s):  
Johannes Walter ◽  
Dieter Wurz ◽  
Stefan Hartig ◽  
Martin Gabi
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Outer Wall ◽  
Pressure Recovery ◽  
Shear Stresses ◽  
Axial Fan ◽  
Mean Velocity ◽  
Annular Diffuser ◽  
Axial Fans ◽  
Wall Shear

Axial fans are used in power plants for fresh air supply and flue gas transport. A typical configuration consists of an axial fan and annular diffuser which connects the fan to the following piping. In order to achieve a high efficiency of the con-figuration, not only the components have to be optimized but also their interaction. The present study focuses on the diffuser of the configuration. Experiments are performed on a diffuser-piping configuration to investigate the influence of the velocity profile at the fan outlet on the pressure recovery of the configuration. Two different diffuser inlet profiles are generated, an undisturbed profile and a profile with the typical outlet characteristics of a fan. The latter is generated by the superposition of screens in the inlet zone. The tests are conducted at a high Reynolds number (Re ? 4?105). Mean velocity profiles and wall shear stresses are measured with hydraulic methods (Prandtl and Preston tubes). The results show that there is a lack of momentum at the outer wall of the diffuser and high shear stresses at the inner wall in case of the undisturbed inflow profile. For the typical fan outlet profile it is vice versa. There are high wall shear stresses at the outer wall while the boundary layer of the inner wall lacks momentum. The pressure recovery of the undisturbed inflow configuration is in good agreement with other studies.

scholarly journals Numerical analysis of axial fan characteristics

Mechanik ◽  
2018 ◽  
Vol 91 (7) ◽  
pp. 606-608
Author(s):  
Stanisław Wrzesień ◽  
Michał Frant ◽  
Maciej Majcher
Keyword(s):  
Numerical Analysis ◽  
Numerical Methods ◽  
Flow Rate ◽  
Total Pressure ◽  
Volumetric Flow Rate ◽  
Total Efficiency ◽  
Axial Fan ◽  
Axial Fans ◽  
Basic Characteristics

The paper presents an analysis and comparison of basic characteristics of axial fans, both analytically and numerically. Such characteristics are: the characteristics of the total pressure, power and total efficiency as a function of the volumetric flow rate. The presented results showed significant quantitative and qualitative differences in the characteristics obtained by two methods. The usefulness of numerical methods in relation to the results of the initial analytical project was confirmed.

scholarly journals Análise dos constructos comportamentais do empreendedorismo sustentável de estudantes universitários brasileiros

2019 ◽  
Vol 12 (4) ◽  
pp. 718
Author(s):  
Luis Eduardo Brandão Paiva ◽  
Tereza Cristina Batista de Lima ◽  
Silvia Maria Dias Pedro Rebouças ◽  
Rômulo Alves Soares
Keyword(s):  
University Students ◽  
Entrepreneurial Intention ◽  
Positive Influence ◽  
Entrepreneurial Intentions ◽  
Sustainable Entrepreneurship ◽  
Academic Context ◽  
Entrepreneurial Intent ◽  
Entrepreneurial Activities ◽  
The University ◽  
Behavioral Constructs

Research on entrepreneurial intention stands out in the academic context and addresses several determinants related to the behavioral nature influencing entrepreneurship. Consequently, the following behavioral constructs were used for sustainable entrepreneurship: attitude towards self-employment; orientation towards sustainability; propensity to innovate; barriers and facilities for entrepreneurial activities; and entrepreneurs in the immediate family. This study aimed to analyze the influence of the behavioral constructs of sustainable entrepreneurship on the entrepreneurial intentions of university students. Based on a sample of 318 students enrolled on an administration course at the Federal University of Ceará, statistical techniques of data analysis were applied, namely factorial analysis, inferential statistics (t-test and Mann-Whitney test), logistic regression and Classification and Regression Trees (CART). Three hypotheses were constructed in this study based on the literature: (i) there is a positive influence between the orientation towards the sustainability of university students and their entrepreneurial intention, (ii) there is a positive influence between the propensity to innovate and the entrepreneurial intention of the university students, and (iii) having entrepreneurs in the immediate family contributes positively to the entrepreneurial intent of university students. It was noted that, in general, students most likely to have entrepreneurial intent are those most concerned with environmental issues, that are stimulating and original, and have immediate relatives that are entrepreneurs.

scholarly journals Improving the performance of the air-cooling unit in the cooling system of a radar

2021 ◽  
Vol 2057 (1) ◽  
pp. 012004
Author(s):  
Yu A Borisov ◽  
V V Volkov-Muzilev ◽  
D A Kalashnikov ◽  
H S Khalife
Keyword(s):  
Heat Exchanger ◽  
Gas Flow ◽  
Cooling System ◽  
Experimental Studies ◽  
Air Cooling ◽  
Axial Fan ◽  
Gas Dynamic ◽  
Cooling Unit ◽  
Calculation Results ◽  
Axial Fans

Abstract The article discusses the issues of reducing the size of the cooling unit of the antenna of a radar station by improving the gas-dynamic processes occurring in the air-cooling unit. The results of the experimental studies of the gas flow in a plate-fin heat exchanger, being blown by one axial fan are presented. The feasibility of changing the number of axial fans for organizing a more uniform flow around the heat-exchange surfaces has been determined by calculation and theoretical methods. The calculation results are confirmed by experimental studies of the air flow in the segment of the heat exchanger, which is provided by a smaller fan.

Sign in / Sign up

Export Citation Format

Share Document