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Investigation Of The Effects Of Various Parameters On A Subsonic Axial Flow Fan Performance And Tonal Noise
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Book Synopsis Investigation of The Effects Of Various Parameters On A Subsonic Axial Flow Fan Performance And Tonal Noise by : Racheet Matai
Download or read book Investigation of The Effects Of Various Parameters On A Subsonic Axial Flow Fan Performance And Tonal Noise written by Racheet Matai and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work was aimed at improving the efficiency and decrease the noise generated by a cooling fan used by GE transportation to cool a row of resistor networks which dissipate excess energy generated by regenerative power in an inverter application. The first part of study focused on determining the effect of various parameters on the performance of the fan quantitatively by using FLUENT, a general purpose CFD code. The effects of parameters such as hub to tip ratio, chord length/thickness and solidity/number of blades was studied. Once the effect of these parameters was found a new fan was designed which increased the efficiency at the operating point from 73% to 77%. This new fan had a longer blade (increased by 0.75 inches), less number of blades (24 reduced to 18) and a larger chord length (the airfoil scaled by 1.5 time). The hub shape was also modified to reduce separation at the hub. Although a more efficient design, this new fan was found to make more noise with the peak dB levels increasing from 89dB to 110dB due to a higher rate of change of axial force on blades which is proportional to the sound pressure level. Thus a different approach was adopted, an inlet guide vane (IGV) with different lean angles were experimented with. It was seen that a 6 degree lean angle eliminated the peak at the first harmonic of the blade pass frequency (2400Hz) and a 15 degree lean angle eliminated the first and the second harmonic of the blade pass frequency (2400Hz and 3600Hz). The first peak at the blade passing frequency remained approximately the same (~89dB) with the IGV lean.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1993 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Study of Two Counter Rotating Axial Flow Fans by : Juan Wang
Download or read book Experimental Study of Two Counter Rotating Axial Flow Fans written by Juan Wang and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT : The counter rotating subsonic axial flow fans could be a good solution for applications where the highly improved static pressure and efficiency are required without the increase of rotational speed and fan diameter. However, the mechanisms of high performance CRS and parameters influences are not well understood nowadays. This thesis is an experimental investigation of the performance and parameter studies of two counter rotatingaxial flow ducted fans. The design and measurement methods are based on the previous research work in Laboratory Dynfluid (Arts et Métiers ParisTech). Three Counter Rotating Stages (CRS) (named JW1, JW2 and JW3) are developed and tested on a normalized test bench (AERO2FANS). These systems have same design point and differ by the distribution of loading as well as the ratio of angular velocity between the Front Rotor (FR) and Rear Rotor (RR). The first part of results focus on the JW1. The overall performance is obtained by the experimental results of the static pressure rise and static efficiency, as well as the wall pressure fluctuations recorded by a microphone on the casing wall. The parameter study is conducted to investigate the effects of the axial distance and the ratio of angular velocity between the FR and RR on the global performance and flow fields measured by Laser Doppler Velocimetry (LDV).The last part of the work is devoted to analyze the differences of the three CRS with different distribution of work, in terms of the global performance and flow features.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1977 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Inflow Conditions on Discrete Frequency Noise Generated by Small, Axial Flow Fans by : K. B. Washburn
Download or read book Effects of Inflow Conditions on Discrete Frequency Noise Generated by Small, Axial Flow Fans written by K. B. Washburn and published by . This book was released on 1985 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discrete frequency acoustic radiation is generated by subsonic axial flow fans through both steady and unsteady blade loading. Steady loading is a function of pumping requirement, and unsteady loading is generated by spatially periodic inflow distortions. The latter effect is the dominant generation mechanism when small fans are used to cool electronic equipment. Fans mounted to exhaust out of a device ingest distortions created by all objects within the unit. This work represents an empirical survey of noise generated by small axial flow cooling fans in the presence of upstream obstructions and various inlet configurations. the obstructions include a cylinder, a thin rectangle, a thick rectangle, and an electronic card gate model. Each of these represents obstructions found in a typical installation. Simple and modified inlet baffles, finger guards, and honeycomb flow straighteners are investigated. Design recommendations are offered to minimize discrete tone generation. These include aerodynamic shaping of unaviodable obstructions, a minimum axial distance of 0.3 fan radii for obstructions in the inlet, the avoidance of blockage in lateral inflow and the use of an inlet baffle to smooth inlet distortions. Account is taken of the spatial restictions of typical installations.
Download or read book Transportation Noise Bulletin written by and published by . This book was released on 1972 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Influence of Wall Boundary Layer Upon the Performance of an Axial-flow Fan Rotor by : Emanuel Boxer
Download or read book Influence of Wall Boundary Layer Upon the Performance of an Axial-flow Fan Rotor written by Emanuel Boxer and published by . This book was released on 1951 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation has been conducted to determine the effects of the wall boundary layer upon the performance of an axial-flow fan rotor. Tests were conducted at low Mach numbers and at one blade angle on a fan designed to have uniform downstream tangential velocity. The maximum disturbed-flow region of the six boundary-layer configurations tested exceeded one-half of the annular width of the duct and the peak efficiency was reduced 2 1/2 percent for this condition. The over-all loss in efficiency may possibly be reduced by decreasing the blade pitch angle in the boundary-layer region to conform to the upstream velocity profile.
Book Synopsis Bibliography of Lewis Research Center Technical Publications Announced in 1977 by : Lewis Research Center
Download or read book Bibliography of Lewis Research Center Technical Publications Announced in 1977 written by Lewis Research Center and published by . This book was released on 1978 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: This compilation of abstracts describes and indexes over 780 technical reports resulting from the scientific and engineering work performed and managed by the Lewis Research Center in 1977. All the publications were announced in the 1977 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Documents cited include research reports, journal articles, conference presentations, patents and patent applications, and theses.
Book Synopsis Masters Theses in the Pure and Applied Sciences by : Wade H. Shafer
Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2013-12-11 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and dis seminated by the Center for Information and Numerical Data Analysis and Synthesis, (CINDAS) *at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the ac tivity was transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volume were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 19 (thesis year 1974) a total of 10,045 theses titles from 20 Canadian and 209 United States universities. We are sure that this broader base for theses titles reported will greatly enhance the value of this important annual reference work. The organization of Volume 19 is identical to that of past years. It consists of theses titles arranged by discipline and by university within each discipline.
Download or read book NASA SP. written by and published by . This book was released on 1992 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronautical Engineering written by and published by . This book was released on 1971 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA)
Book Synopsis Analytical Parametric Investigation of Low Pressure Ratio Fan Noise by : F. B. Metzger
Download or read book Analytical Parametric Investigation of Low Pressure Ratio Fan Noise written by F. B. Metzger and published by . This book was released on 1973 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of an analytical study are reported which shows the effect of various physical and operating parameters on noise produced by low pressure ratio propulsive fans operating at subsonic top speeds. Acoustical duct lining effects are included in the study. The concepts used to develop the noise theory used in the study, as well as the correlation between the theory and model test results are also presented. It is shown that good correlation has been established between theory and experiment. Using the theory, it is shown that good aerodynamic design, maximum acceptable fan solidity, low tip speed operation and use of few blades and vanes leads to the lowest noise levels. Typical results of the study indicate that a fan operating at 1.2 fan pressure ratio and 700 ft/second tip speed with 12 blades and 7 vanes and including modest acoustic treatment on the duct wall would produce levels allowing a 100,000 lb. STOL aircraft to meet a noise level objective of 95 PNdB at 500 ft at takeoff.
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Note written by and published by . This book was released on 1974 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigation of the Effects of Inlet Shapes on Fan Noise Radiation by : T. L. Clark
Download or read book Investigation of the Effects of Inlet Shapes on Fan Noise Radiation written by T. L. Clark and published by . This book was released on 1981 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of inlet shape on forward radiated fan tone noise directivities was investigated under experimentally simplified zero flow conditions. Simulated fan tone noise was radiated to the far field through various shaped zero flow inlets. Baseline data were collected for the simplest baffled and unbaffled straight pipe inlets. These data compared well with prediction. The more general inlet shapes tested were the conical, circular, and exponential surfaces of revolution and an asymmetric inlet achieved by cutting a straight pipe inlet at an acute angle. Approximate theories were developed for these general shapes and some comparisons with data are presented. The conical and exponential shapes produced directivities that differed considerably from the baseline data while the circular shape produced directivities similar to the baseline data. The asymmetric inlet produced asymmetric directivities with significant reductions over the straight pipe data for some angles.
Book Synopsis Aeronautical Engineering: A Cumulative Index to a Continuing Bibliography (supplement 274) by :
Download or read book Aeronautical Engineering: A Cumulative Index to a Continuing Bibliography (supplement 274) written by and published by . This book was released on 1992 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt:
