Characteristics Of Fan Research Articles

Comparison of performance characteristics of SCR and ECM controlled series fan powered terminal units

Airflow, efficiency, power, and power quality characteristics were evaluated for two variable air volume series fan powered terminal units. The power and power quality data included real power, power/airflow, apparent power, harmonic frequencies, and total harmonic distortion. Each unit had the same sized primary air inlet and were provided by the same manufacturer. One unit had a motor controlled by a silicon controlled rectifier and the other had an electronically commutated motor. Data were collected at a fixed downstream static pressure and a range of upstream static pressures, primary inlet damper positions, and input controller voltages. Both controllers maintained a nearly constant fan airflow as the primary air was varied. Fan/motor efficiencies were low (below 35%) and increased with fan static pressures. The electronically commutated motor unit had efficiencies as much as four times higher than the silicon controlled rectifier controlled unit which was reflected in much lower power draws. The electronically commuted fan/motor unit had the lowest apparent power at airflows below approximately 1000 ft3/min (0.47 m3/s). For both units, the total power harmonic distortion was less than 1%. The performance data indicated a major advantage of units with electronically commutated motors.

Sedimentary characteristics and tectonic setting of sublacustrine fans in a half-graben rift depression, Beibuwan Basin, South China Sea

Drilling has shown that there is a large petroleum reserve in the Liushagang Formation of the Fushan Depression, South China Sea from reservoirs of the sublacustrine fans. To reduce the risk associated with exploration, the sedimentary characteristics of the sublacustrine fans should be identified and described. Analysis of the drilling cores, well data and 3D seismic data was conducted to identify and interpret the sublacustrine fans which formed in a lacustrine succession as the low-stand fan of the 2nd member of Liushagang Formation (SQEls2). The reservoirs were commonly associated with pebbly conglomerates, mudstone shivers, muddy debris, various deformation structures including micro-faults, liquified deformation structure, ball and pillow structure, slump and stress-release deformation. Further contrastive analysis of sedimentary characteristics and palaeogeomorphology between the western and eastern sublacustrine fans indicates that they belong to two different types of sublacustrine system in continental basins. More specifically, the western fan, controlled by the multi-level step-fault belt, is a typical gravel-rich sublacustrine system which is characterised by structurally controlled, high gradient (2.8–3.3°), admixtures of muddy debris and pebbly conglomerates and poor reservoir quality, while the eastern fan, controlled by the flexure slope-break belt, is a sand-rich sublacustrine system dominated by relatively low gradient (2.0–2.5°), general fining-upwards trend with good reservoir quality. Therefore, the development of future exploration should be conducted at different levels in the Fushan Depression.

1014 障害物近傍に置かれた小型軸流ファンの性能特性

The system requirements of axial flow fans are various. It is often seen that the axial flow fans are used under the inadequate operating condition. In recent downsizing equipment design, the cases where some obstacles installed in upstream of fans for device densification are increasing. In the present study, an attempt is made to clarify the influence of an upstream obstacle on the performance characteristics of axial flow fan. Furthermore, the flow instabilities around the fan with the obstacle are discussed.

J0910205 四角ケーシングを有するターボファンの騒音特性 : ケーシング干渉物の影響([J091-02]流体関連の騒音と振動(2))

The backward-curved centrifugal fan with rectangular casing is used to the air conditioners and the air cleaners that is required the compact and flexible design. We have pointed out that the performance of the fan is better than the fan with scroll casing at the large flow rate. But the noise characteristics of this type fan are not cleared yet. It is investigated the noise characteristics in relating to the interaction between the impeller and the rectangular casing by experiments and numerical simulation. It is pointed out that the interaction noise is lower than the fan with scroll casing. The turbulent noise is consists from the three frequency ranges that have the different noise sources. The low frequency range noise is generated from the impeller, the middle frequency range noise is generated from the casing wall and the high frequency range noise is generated from the shroud. The secondary flow near the shroud causes the large turbulence and generates the high frequency and large turbulent noise. We proposed the obstacle setting to reduce the noise level.

Flow and Noise Characteristics of Centrifugal Fan under Different Stall Conditions

An implicit, time-accurate 3D Reynolds-averaged Navier-Stokes (RANS) solver is used to simulate the rotating stall phenomenon in a centrifugal fan. The goal of the present work is to shed light on the flow field and particularly the aerodynamic noise at different stall conditions. Aerodynamic characteristics, frequency domain characteristics, and the contours of sound power level under two different stall conditions are discussed in this paper. The results show that, with the decrease of valve opening, the amplitude of full pressure and flow fluctuations tends to be larger and the stall frequency remains the same. The flow field analysis indicates that the area occupied by stall cells expands with the decrease of flow rate. The noise calculation based on the simulation underlines the role of vortex noise after the occurrence of rotating stall, showing that the high noise area rotates along with the stall cell in the circumferential direction.

20601 小型多翼ファンの流れの不安定現象に関する研究

An experimental study was made to clarify the fundamental flow characteristics of Sirocco fans. Using fan's height is 115mm, inlet radius is 80mm, outlet radius is 90mm, vane angle is 150 degree, number of vanes is 52. This fan rotates with 23.75Hz. The oscillations of the radial velocity in the sirocco fan installed in the open space were measured by the hot wire probe. By FFT analysis, the two magnitude peaks of the radial velocity were found and the two significant peaks were found. The first peak was found at 19Hz and has the three cells rotating with the rotation of the impeller. The second peak was found at 33Hz and has the four cells rotating with the rotation of the impeller.

Numerical study on air-structure coupling dynamic characteristics of the axial fan blade

In order to understand the dynamic characteristics of the axial-flow fan blade due to the effect of rotating stress and the action of unsteady aerodynamic forces caused by the airflow, a numerical simulation method for air-structure coupling in an axial-flow fan with fixed rear guide blades was performed. The dynamic characteristics of an axial-flow fan rotating blade were studied by using the two-way air-structure coupling method. Based on the standard k-ε turbulence model, and using weak coupling method, the preceding six orders modal parameters of the rotating blade were obtained, and the distributions of stress and strain on the rotating blade were presented. The results show that the modal frequency from the first to the sixth order is 3Hz higher than the modal frequency without considering air-structure coupling interaction; the maximum stress and the maximum strain are all occurred in the vicinity of root area of the blade no matter the air-structure coupling is considered or not, thus, the blade root is the dangerous location subjected to fatigue break; the position of maximum deformation is at the blade tip, so the vibration of the blade tip is significant. This study can provide theoretical references for the further study on the strength analysis and mechanical optimal design.

The application of sinusoidal blade-leading edges in a fan-design methodology to improve stall resistance

Taking inspiration from previous biomimetic studies on the performance of humpback whale flippers, this paper reports a programme of work to design a ‘whale-fan’ that incorporates a sinusoidal leading-edge blade profile that mimics the tubercles on humpback whales flippers. Previous researchers have used two-dimensional cascades of aerofoils to study the effects of a sinusoidal profile on aerofoil lift and drag performance. The research was primarily concerned with elucidating the fluid-flow mechanisms induced by the sinusoidal profile and the impact of those mechanisms on aerofoil performance. The results indicate that a sinusoidal leading-edge profile has improved lift recovery post-stall and, thus, is inherently more aerodynamically resistant to the effect of stall. The reported research focuses on the application of previous research conducted with infinite span cascades of aerofoils to the design and optimisation of a finite span aerofoil. The paper presents the assumptions when developing a three-dimensional aerofoil-design methodology that correlates the sinusoidal profile of the blade-leading edge with the desired vorticity distribution at the trailing edge. The authors apply the developed methodology to the design of a fan blade’s tip region to control separation at the trailing edge. The paper presents numerically derived whale-fan performance characteristics and compares them with both numerically and experimentally derived performance characteristics of the baseline fan.

Patterns of intercalation in alluvial fan reservoirs—A case study of Lower Karamay Formation, Yizhong Area, Karamay Oilfield, NW China

Abstract This paper discusses the overall distribution characteristics of alluvial fan in the Triassic Lower Karamay Formation, Yizhong Area, the Karamay Oilfield, with core, outcrop, logging and seismic data. On this basis, the shapes, sizes and stacking patterns of intercalations in different levels and sub-facies are analyzed using the hierarchy bounding surfaces method. In the study area, the Lower Karamay Formation contains (from bottom to top) root fan, middle fan and outer fan deposits, with size-reducing grains, as a complete retrograding sedimentary sequence. The intercalation in the alluvial fan reservoir can be divided into two types: lithological intercalation (fine sediments) and physical intercalation (argillaceous sandstone/conglomerate). Origin, pattern and size of intercalations vary significantly in different sub-facies zones. In particular, the intercalations in root fan are “scattered generally and interlaced locally”, presenting as partially discontinuous screen in a high-permeable network; the intercalations in middle fan are relatively stable intercalations and lateral intercalations, with a higher capacity to shade or screen the seepage; the intercalations in outer fan present as a layered cake, with reservoir bodies mosaic-like along the source and lenticular in perpendicularity to the source that are separated by thick barrier beds, showing the highest capacity of screen.

Prediction of dynamic and aerodynamic characteristics of the centrifugal fan with forward curved blades

The main aim of this paper is determine the centrifugal fan with forward curved blades aerodynamic characteristics based on numerical modeling. Three variants of geometry were investigated. The first, basic “A” variant contains 12 blades. The geometry of second “B” variant contains 12 blades and 12 semi-blades with optimal length [1]. The third, control variant “C” contains 24 blades without semi-blades. Numerical calculations were performed by CFD Ansys. Another aim of this paper is to compare results of the numerical simulation with results of approximate numerical procedure. Applied approximate numerical procedure [2] is designated to determine characteristics of the turbulent flow in the bladed space of a centrifugal-flow fan impeller. This numerical method is an extension of the hydro-dynamical cascade theory for incompressible and inviscid fluid flow. Paper also partially compares results from the numerical simulation and results from the experimental investigation. Acoustic phenomena observed during experiment, during numerical simulation manifested as deterioration of the calculation stability, residuals oscillation and thus also as a flow field oscillation. Pressure pulsations are evaluated by using frequency analysis for each variant and working condition.

The Map Fitting Tool Methodology: Gas Turbine Compressor Off-Design Performance Modeling

This paper describes the structure and the implementation of an extended parametric representation of compressor characteristics for a modern object oriented gas turbine performance simulation software (PROOSIS). The proposed methodology is the map fitting tool (MFT) methodology. The proposed MFT methodology for modeling the off design performance of gas turbine turbomachinery components (fans, compressors, and turbines) is based on a concept conceived and developed collaboratively by General Electric (GE) and NASA. This paper provides a short description of both BETA and MFT compressor maps, as well as the development of compressor component models in PROOSIS capable of using both types of maps for off design compressor performance prediction. The work presented in this paper is the outcome of a collaborative effort between Snecma Moteurs and Cranfield University as part of the European Cycle Program of the EU FP6 collaborative project—VIVACE. A detailed description of the MFT map methodology is provided with a “step-by-step” calculation procedure. Synergies between compressor MFT and compressor BETA calculations are also highlighted and a description of how these two components have been integrated into an object oriented simulation software with component hierarchy is also presented. Advanced parametric representations of fan and turbine characteristics have also been developed within PROOSIS. However, a description of these methodologies is beyond the scope of this publication. Additionally, a comparison between the advantages and disadvantages between BETA and MFT maps is an interesting debate. However, this is also beyond the scope of this paper.

Research on Hover Characteristics of Ducted Fan with Coaxial Rotors

The method of handling respectively is used to refine the grid of ducted fan with coaxial rotors. Research the complex flow field of the ducted fan by numerical simulation to analyze its hover characteristics. The curve of the upper rotors lift, the lower rotors lift, the ducts lift with collective and the distance between rotors is got respectively. By comparing with the aerodynamic characteristics of ducted fan with a single rotor, results show that there is interference between the upper and lower rotors, the upper one interferes the lower one more heavily and interference is reduced with the increase of distance between the rotors; the duct of ducted fan with coaxial rotors can provide more lift than the one with a single rotor.

원심형 보조날개를 부착한 축류홴의 유동특성에 관한 실험적 연구

A new type axial flow fan with centrifugal sub-blades has been designed and fabricated in the present study. We investigated velocity and pressure distributions in downstream flow fields of the fan experimentally to detect the detailed flow characteristics of new axial flow fan and an existing axial flow fan. Two-dimensional velocity components were probed by applying a particle image velocimetry system and pressure distributions were measured by Pitot tube and micro-manometer. Our results show that the velocity and pressure distributions at the flow fields of the new fan are quite different from the existing fan, and that the centrifugal sub-blades in the new fan can improve the performance characteristics in view of kinetic energy.

Adaptation of main mine fan aerodynamics to vent mode changes

The authors illustrate efficient adaptability of aerodynamic characteristics of main mine fans to changes in mine vent modes in the course of mine’s operating life by using fan impellers with replaceable sheet blades of different aerodynamic configurations.

Characteristics of the turbidite fan in the Wenchang Formation of the Enping Sag, Pearl River Mouth Basin, China and its hydrocarbon significance

A turbidite fan in the Eocene upper Wenchang Formation in the Enping Sag, Pearl River Mouth Basin (PRMB) has been studied using seismic, logging and borehole data. The fan is characterized by parallel progradation on the dip seismic profile and is mound-shaped or lenticular-shaped on the strike seismic profile. The study of the core and logging data from well EP17-3-1, which is located in the front side of the turbidite fan, shows that this fan is a set of normal grading sand beds, interbedded within thick dark grey mudstones of semi-deep to deep lake deposits in the Wenchang Formation. The fan is interpreted as a sand/mud-rich turbidite fan that has an area of over 140km2 and a maximum thickness of over 340 m. Combined with a study of the regional geological background and previous provenance analysis of the Eocene Wenchang Formation, the main potential provenances for the turbidite fan are considered to be the Panyu low-uplift and northern fault terrace zone. The Enping Sag is considered to be a half graben-like basin whose north side is faulted and whose south side is overlapped. Basement subsidence in the Eocene was mainly controlled by boundary faults which dip relatively steeply on the north side, causing the subsidence center of the Enping Sag in this stage to be close to the north boundary faults. Sustained faults developed in the Enping Sag during the Eocene caused an increase of the relative height difference between the north and the south uplift zone in the Enping Sag. Affected by the second episode of the Zhuqiong movement (39–36 Ma) in late Eocene, sediments which had accumulated on the Panyu low-uplift zone were triggered and moved toward the subsidence center of the Enping Sag and formed the turbidite fan. The second episode of the Zhuqiong movement is the most important triggering factor for the formation of the turbidite fan in the Wenchang Formation. Seismic attribute characterization shows that the low frequency energy is enhanced and high frequency energy is weakened when seismic waves propagate through the oil-bearing zone in this fan. Amplitude versus offset (AVO) anomalies are observed in the seismic data and abnormally high pressure is encountered. The turbidite fan in the Wenchang Formation has provided important information for sedimentary evolution in deep layers of the Enping Sag and pointed to a new direction for the hydrocarbon exploration in the study area.

Numerical and experimental study on aerodynamic performance of small axial flow fan with splitter blades

To improve the aerodynamic performance of small axial flow fan, in this paper the design of a small axial flow fan with splitter blades is studied. The RNG k-ɛ turbulence model and SIMPLE algorithm were applied to the steady simulation calculation of the flow field, and its result was used as the initial field of the large eddy simulation to calculate the unsteady pressure field. The FW-H noise model was adopted to predict aerodynamic noise in the six monitoring points. Fast Fourier transform algorithm was applied to process the pressure signal. Experiment of noise testing was done to further investigate the aerodynamic noise of fans. And then the results obtained from the numerical simulation and experiment were described and analyzed. The results show that the static characteristics of small axial fan with splitter blades are similar with the prototype fan, and the static characteristics are improved within a certain range of flux. The power spectral density at the six monitoring points of small axial flow fan with splitter blades have decreased to some extent. The experimental results show sound pressure level of new fan has reduced in most frequency bands by comparing with prototype fan. The research results will provide a proof for parameter optimization and noise prediction of small axial flow fans with high performance.

Design and Experimental Studies of Radial-Outflow Type Diagonal Flow Fan

In order to apply the design method of diagonal flow fan based on axial flow design to the design of radial-outflow type diagonal flow fan which has lower specific speed of 600-700 [, , m], radial-outflow type diagonal flow fan which specific speed was 670 [, , m] was designed by a quasi three-dimensional design method. Experimental investigations were conducted by fan characteristics test, flow surveys by a five-hole probe and a hot wire probe. Fan characteristics test agreed well with the design values. In the flow survey at rotor outlet, the characteristic region was observed. Two flow phenomena are considered as the cause of the characteristic region, one is tip leakage vortex near rotor tip and another is pressure surface separation on the rotor blade.

Vibration and Noise Characteristics of Line Flow Fan for Railroad Car

Vibration and Noise Characteristics of Line Flow Fan for Railroad Car

Study on Flow Fields and Noise Characteristics of a Small Axial Flow Fan Used in Narrow Space

Study on Flow Fields and Noise Characteristics of a Small Axial Flow Fan Used in Narrow Space

Design of Half-Ducted Axial Flow Fan Considering Radial Inflow and Outflow

Half-ducted fan and ducted fan have been designed and numerically analyzed for investigating the radial flow effect on the overall performance and the three dimensional flow field in design. Based on quasi-three dimensional flow theory, the meridional flow was calculated by adopting the radial balance equations, while the calculation of the blade to blade flow was obtained by 2D cascade data with the correction by a potential flow theory. Two types of axial flow fan were designed. One is the full ducted case as if it was in the straight pipe and another is the half-ducted case with the radial inflow and outflow. The previous experimental results of authors were used to decide the inclinations of both the inflow and outflow. And the circular arc blade with equal thickness was adopted. The numerical results indicate that both of the designed fans can reach the specified efficiency and also the efficiency surpasses more than 11%. Furthermore, the static pressure characteristic of half-ducted fan is much better than that of ducted fan. In comparison of the three dimensional internal flow of these two fans, the improvement of the flow angle at inlet and outlet, the distributions of velocity in the flow field and the pressure distributions on the blade surfaces can be achieved more successfully in accordance with the design intension on consideration of flow angle in design. The conclusion that half-ducted design with considering radial inflow and outflow is feasible and valid in comparison with ducted design for axial flow fans has been obtained at the end of the paper.