Top PDF Axial Flow Fan Design by Lattice Theory

Axial Flow Fan Design by Lattice Theory

Axial Flow Fan Design by Lattice Theory

THREE PEASE VAR3[ARLE FREQUENCY PC'VER SUPPLY.[r]

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Correlation between Aerodynamic Noise and Velocity Fluctuation of Tip Leakage Flow of Axial Flow Fan

Correlation between Aerodynamic Noise and Velocity Fluctuation of Tip Leakage Flow of Axial Flow Fan

In the present paper the attention is focused on correlation between fan noise and velocity fluctuations of tip leakage vortex around rotor blade of a low pressure axial flow fan at the maximum pressure operating point. We measured time fluctuating velocity near the rotor tip around the rotor blades by using a hot-wire sensor from a relative flame of refer- ence fixed to the rotor blades. As the results, it is clear that the velocity fluctuation due to tip leakage vortex has weak periodicity and the hump portion appeared in its spectrum. If the flow rate was lower than the design condition, the tip leakage flow became to attach to the following blade and the sound pressure level at frequency of velocity fluctuation of this flow was increased. The correlation measurements between the velocity fluctuation of tip leakage flow and the aerodynamic noise were made using a rotating hot-wire sensor near the rotor tip in the rotating frame. The correlation between the velocity fluctuation due to tip leakage flow and acoustic pressure were increased due to generation of weak acoustic resonance at the maximum pressure operating point.
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A Calibration Method of Cylindrical Sensor of Radial Force Based on Axial Flow Fan

A Calibration Method of Cylindrical Sensor of Radial Force Based on Axial Flow Fan

Abstract. A device of calibration using eccentric axial flow fan was designed to calibrate the sensor of radial force. In this paper, centrifugal force generated by eccentricity of rotor of axial flow fan is used to simulate the excitation of the sensor. The internal system of detection and recording is used for data recovery and processing to obtain response and characteristics. After the test of cylindrical sensor with a range of 0-200N, the radial force is linearly related to the output value of ADC. By using the least square method, the outgoing degree is 2.25%, and the sensitivity is 53.3LSB/N. The method verifies the accuracy of the method, and the sensitivity of the maximum deviation is not greater than 1.0LSB/N using the standard force loading at 0°, 60°, 120°, 180°, 240° and 300°. This method provides an effective means for the analysis, design, improvement and manufacture of cylindrical sensors of radial force.
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A Study on the Half Ducted Axial Flow Fan Designed by a Diagonal Flow Fan Design Method

A Study on the Half Ducted Axial Flow Fan Designed by a Diagonal Flow Fan Design Method

A lot of axial fans, which are small size and high efficiency, are used in our daily life, such as a power unit cooling fan of personal computer, a room ventilation fan, and a radiator fan in car engine room. In most applications of fans non- ducted types are used for the space limitation or cost saving. In comparison with the conventional full-ducted fan mainly used in industrial applications, they are called as half-ducted type, semi-opened type and opened type, respectively. Among these types, a half-ducted axial flow fan is focused in this paper. The corresponding design methods for half-ducted types of propeller fans are not studied by many researchers. Recently, many of fans are designed by the inverse design method [1] [2] [3]. A half-ducted axial flow fan is usually designed pro- vided that both the inflow and the outflow are full-ducted as if it were in the straight pipe. However, in our previous result [4] [5], a half-ducted axial flow fan has much more complicated and three-dimensional internal flow than a full- ducted fan. All conventional design methods are not taking the radial velocity component into account. In this paper, the radial inclinations of meridional streamline were considered for the improvement of the design method by using the diagonal flow fan design method. The half-ducted axial flow fans are de- signed by the controlled vortex design by specifying the constant tangential ve- locity both at inlet and outlet of the rotor. Conventional half-ducted fan is usually designed to prescribe almost uniform inflow and outflow as if it was in the straight pipe. However, many axial flow fans are not used in the straight pipe, such as the application of using in the ventilation and cooling systems without pipe. Thus it is important to take the real flow situation into account in design. Therefore, half-ducted axial flow fan was designed to compare with the traditional design of ducted ones by specifying the flow angles according to the previous experimental results of authors [4] [5].
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A Computational Method for Evaluating the Installation Effects of Axial Flow Fan System Noise.

A Computational Method for Evaluating the Installation Effects of Axial Flow Fan System Noise.

Much of the work on fan noise has been related to the development of aircraft. Early in aviation, there was a desire to understand the noise generated from a propeller. This evolved to extensive work by aircraft engine manufacturers such as Pratt and Whitney and within NASA. Though some of this work eventually found its way into the auto- motive industry, there was historically little effort placed into low noise cooling system design. The problem of fan noise in automobiles was largely out weighed by the market demand for low cost [34]. As emissions and performance requirements drove larger and larger cooling systems, the need for better performance from the cooling systems grew. Consumer products such as personal computers, appliances and HVAC systems have also experienced the need for quiet fan system design. Current research is focusing on more efficient heat transfer and quieter systems - in effect more airflow per dB.
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AERODYNAMIC DESIGN OF AXIAL FLOW COMPRESSOR

AERODYNAMIC DESIGN OF AXIAL FLOW COMPRESSOR

Lingen Chen et al.[7] , 2004, presented a model for the optimum design of a compressor stage with assuming fixed axial velocities distribution. The absolute inlet and exit angles of the rotor are taken as design variables. The optimum relation between the isentropic efficiency and the flow coefficient, the work coefficient, the flow angles and the degree of reaction of the compressor stage has been obtained using one-dimensional flow-theory .they provided a numerical example are provided to illustrate the effects of various parameters on the optimal performance of the compressor stage. The calculation of the stage performance is performed using one-dimensional flow-theory. The analysis begins from the energy equation and continuity equation. The other assumptions take as the working fluid is compressible, non-viscous and adiabatic and it flows stably relative to stator and rotor, which rotates at a fixed speed. The mass-flow rate of the working fluid is also constant.
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Design and Optimization of Axial Flow Compressor

Design and Optimization of Axial Flow Compressor

An axial flow compressor is one in which the flow enters the compressor an axial way (parallel with the hub of rotation), and ways out from the gas turbine, likewise in an axial course. The axial-flow compressor packs its working liquid by first quickening the liquid and after that diffusing it to acquire a weight increment. In an axial flow compressor, air goes starting with one phase then onto the next, each stage raising the weight marginally. The vitality dimension of air or gas flowing through it is expanded by the activity of the rotor cutting edges which apply a torque on the liquid which is provided by an electric engine or a steam or a gas turbine. In this postulation, an axial flow compressor is designed and displayed in 3d modeling programming genius/build. The present design has 30 cutting edges, in this theory it is replaced with 20 sharp edges and 12 edges. The present utilized material is chromium steel; it is replaced with titanium alloy and nickel alloy. Auxiliary examination is done on the compressor models to check the quality of the compressor. Cfd examination is done to check the flow of air..
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Design and Analysis of an Axial Fan applicable for Kiln Shell Cooling

Design and Analysis of an Axial Fan applicable for Kiln Shell Cooling

Designing an efficient airfoil profile implies that the shape which thus acquired has to be aerodynamically efficient. Fan characteristics can be described by consistent parameters such as volume flow rate, pressure, power, and efficiency. An industrial example, upon industrial study, has been considered for the demonstration of the design flow. Based on specifications of site conditions and flow requirements, a preliminary calculations has been made which defined the system resistance. From these considerations a specific valve of fan diameter has obtained, by using Cordier diagram which was verified with background fan curves for an optimal value.
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Flow control in axial fan inlet guide vanes by synthetic jets

Flow control in axial fan inlet guide vanes by synthetic jets

Axial flow stage (rotor and stator blade rows) with inlet guide vanes (figure 2) was used for tests of active flow control. The stage blading, denoted by the abbreviation of AV6, was designed and experimentally verified by AHT Energetika – Cyrus et al. [15]. The outer and inner diameters of stage were constant. The hub/tip ratio is 0.7 and external diameter is 600 mm. The stage cascades have extremely high aerodynamic loading. The profiles of rotor and stator airfoils are NACA 65 – series. Design flow coefficient is φ = 0.60.

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Modeling and performance investigation of axial flow type propeller fan

Modeling and performance investigation of axial flow type propeller fan

Dunn (1983) done experimental analysis of Reverse Act Features of main source fans. During a mine fire or other reserve, it may be looked-for to other the airflow in order to provide an escape way or to isolate a fire. Also, in colder areas, the airflow may be reversed to avoid ice build-up. When reversing main mine fans, the source operator usually does not know what operating characteristics of flow and pressure to expect [3].Yang et.al (2007) wilful the flow mechanism analysis and new study of a forward-skewed impeller and a centrifugal impeller in low force axial fan.The forward-skewed cutting edge was obtained by the optimization design of the radial blade and CFD technique. Depth of the two blades was carried out in aerodynamic and aero sound performance. Related to the circular blade, the forward-skewed blade has confirmed the developments in efficiency [4].The performance of the fan are governed by different fan laws. Hence lot of importance is given to understand the basic theory of fans, their types and their occupied. The choice of critical limitations is very essential while determining the performance of the fans [5].AlirezaFalahat (2011) In this study an attempt was made to find the greatest the best angle of attack and rotational velocity of a flat plate at a fixed hub to tip ratio for a maximum flow magnitude and turbulent conditions. The blade angles are varied from 30 to 70 degrees and the revolving rapidity is
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Numerical Study on Internal Flow of Small Axial Flow Fan with Splitter Blades

Numerical Study on Internal Flow of Small Axial Flow Fan with Splitter Blades

tion of splitter blades to the axial impellers was not suc- cessful and this technology was stalled. Since 1980s, with the development of computer and methods of full three-dimensional numerical simulation, the technology of splitter blade was applied again and it had obtained the significant achievements [4-6]. Tzuoo et al. [7] reviewed the results of a detailed analytical study performed on Wennerstrom’s rotor, followed by the details of a redes- ign effort using advanced design methodology, and the results showed that the extensive flow separation ob- served in Wennerstrom’s rotor can be completely elimi- nated by redesigning the main blade and splitter vane. Yongxin Zhang et al. [8] found that splitter could recon- struct the balance of pressure in rotor passage, and con- trolled the flow near rotor blade. Ming Yan et al. [9] studied flow characteristics of one axial compressor rotor with splitter, they concluded that the rotor with splitter could be operated with higher total pressure ratio, higher efficiency and larger mass flow than normal designed rotors, under the high loaded condition and with the same
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Finite element 
		analysis and optimization design of aluminium axial fan blade

Finite element analysis and optimization design of aluminium axial fan blade

An axial flow fan is a fan to create gas or air flow linearly along the axis of it. That will force air to move parallel to the shaft of blades. That are widely used in cooling, compression and ventilation. Axial fan are usually used by industrial in extreme condition such as large vibration, high temperature and high corrosion. For that reason the components and blades are made out of aluminium, which is lightweight, resistant to extreme environment. Therefore, the axial fan is very important in the ventilation system development in industries. Analysis and experiments have been carried out by several researchers to investigate the behavior both stress and fracture mechanics (Sarraf et al, 2011; Xuemin et al, 2015). Finite element methods (FEM) was used in the analysis of stress, strain, fatique and sheet metal forming as well (Chunxi et al, 2014; Leifur and Slawomir, 2015; Anggono et al, 2014).
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DESIGN & FLOW FEATURES OF AXIAL FAN USED IN AN AIR COOLED HEAT EXCHANGER BY EXPERIMENTAL ANALYSIS

DESIGN & FLOW FEATURES OF AXIAL FAN USED IN AN AIR COOLED HEAT EXCHANGER BY EXPERIMENTAL ANALYSIS

Heat exchanger geometry and area are constant by definition in the fixed plant simulations. However, changes to fluid flow rates will affect the fluid flow regime, equipment operating pressures, and temperature differences throughout each heat exchanger; which in turn will affect fluid physical properties. Changes in the fluid flow regime were assumed to have a greater affect on the overall heat transfer coefficient than changes in fluid properties (viscosity, density, heat capacity, and thermal conductivity).

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Volume Flow Rate Optimization of an Axial Fan by Artificial Neural Network and Genetic Algorithm

Volume Flow Rate Optimization of an Axial Fan by Artificial Neural Network and Genetic Algorithm

A single passage of the axial fan was adopted as the computational domain in this paper to reduce the computation load. The grid distribution of the axial fan impeller is presented in Figure 3. The minimum grid orthogonality is greater than 22.88˚, the maximum aspect ratio is less than 4487 and the maximum ex- pansion ratio is less than 2.76, which meet the NUMECA’s requirements for the grid quality ( orthogonality > 10˚, aspect ratio < 5000, expansion ratio < 5). The inlet and outlet boundary conditions are given as follows: the total pressure is specified at inlet and the static pressure is given at outlet. Actually, the outlet static pressure is set to 0 Pa and the inlet total pressure is set to −25 Pa. In this design, the demanded static pressure of the fan, defined as the difference be- tween the outlet static pressure and the inlet total pressure as shown in Equation (1), is 25 Pa. The fan static pressure efficiency is defined by Equation (2) and the power is calculated according to Equation (3). The rotational speed of the blade is 550 rpm and the periodic boundary condition is employed for the single flow
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Impact of the guard grill on the integral and local characteristics of an axial fan

Impact of the guard grill on the integral and local characteristics of an axial fan

Eck [2] and [3] presented the analytical procedures o f designing axial and centrifugal fans, while Wallis [1] discuss the analytical procedures for designing AF together with inlet and outlet channels. The program m ing and analytical design o f a fan based on a similar basis as described in the literature [1] to [3] was given by Zhou Dugao et al. where the results o f the fan’s optimisation were also presented [17]. A common feature o f the presented literature [ 1 ] to [3] and [17] is that it fails to take into account the impact o f the GG on operating characteristics. Several papers have also been written on experimental and numerical studies o f flow conditions in the AF. The paper by Yang Li et al. [4] , studying the impact o f the direction o f the blade curvature o f similar fans on IC and by five- hole probe and hot wire anemometry the impact on the local vector velocity field, represents the basis for the experimental procedures used in the
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Application of the Ball-Spine Algorithm to Design Axial-Flow Compressor Blade

Application of the Ball-Spine Algorithm to Design Axial-Flow Compressor Blade

methods. One of these physical algorithms is governed by a transpiration model in which one can assume that the wall is porous. Hence, the mass can be ctitiously injected through the wall in such a way that the new wall satises the no ow through the wall boundary condition [10]. This method is aimed to remove nonzero normal velocity on the boundary. A geometry update is determined by applying either the transpiration model based on mass ux conservation [11-15] or the streamline model based on alignments [16]. An alter- native algorithm is based on the residual-correction approach. In this method, the key problem is to relate the computed dierence between actual pressure distribution on the current estimate of the geometry and the TPD (the residual) to the required changes in the geometry. In this method, the art in the development of a residual-correction method is to nd an optimum state between the computational eort (for determining the required geometry correction) and the number of iterations needed to obtain a converged solution. This geometry correction may be estimated by means of a simple correction role, making use of relations between geometry changes and pressure dierences known from linearized ow theory. The residual-correction decoupled solution methods try to utilize the analysis methods as a black-box.
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Unsteady Flow Condition between Front and Rear Rotor of Contra Rotating Small Sized Axial Fan

Unsteady Flow Condition between Front and Rear Rotor of Contra Rotating Small Sized Axial Fan

In order to investigate the large pressure fluctuations near the shroud of the rear rotor, the meridional velocity vectors and vorticity at the design flow rate for L = 10 mm and L = 30 mm is shown in Figure 9 and Figure 10 respectively. The direction of the main flow is from left side to right sight of the paper and the rotational direction of the front rotor is from the front side to back side of the paper and vice versa for the rear rotor. The flow rate is the design flow rate. Crock wise direction of the vorticity is positive and anti-crock wise direction is negative. Regardless of the magnitude of the vectors, the length of the vector is the same. So the velocity vectors show only the direction of the velocity. The vortex of leakage flow from the front rotor tip clearance is observed in Figure 9 and Figure 10 as the blue region for both L = 10 mm and L = 30 mm near the shroud of the casing. The strength of vorticity was kept up to the entrance of the rear rotor for L = 10 mm. Then, the vortex from the front rotor joined with the vortex of the rear rotor; the leakage flow from the front rotor tip clearance joined with the low pressure region associated with the leakage flow of the rear rotor tip clearance. On the other hand, the vorticity of the front rotor became weak near the inlet of the rear rotor for L = 30 mm. These flow conditions re- lated to the leakage flow from the front rotor tip significantly influenced on the pressure fluctuations of the rear rotor near the shroud. The pressure distribu- tions for L = 10 mm and L = 30 mm near the shroud at r / r c = 0.98 are shown in
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Internal Flow Condition between Front and Rear Rotor of Contra Rotating Small Sized Axial Fan at Low Flow Rate

Internal Flow Condition between Front and Rear Rotor of Contra Rotating Small Sized Axial Fan at Low Flow Rate

In the case of the contra-rotating rotors, it is necessary to design the rear rotor considering the unsteady circumferential velocity distributions at the outlet of the front rotor [4]. Further, the fan noise becomes larger than the conventional rotor stator type fan because of the interaction between the front and rear rotors. Then, the passive noise reduction with the perforated blade was proposed for the contra-rotating fan [5]. It is important to clarify the influence of the wake from the front rotor to the rear rotor and the potential interaction between the front and rear rotors to increase the performance and to reduce the fan noise [6]. The blade row distance between the front and rear rotors is a key parameter to con- sider the wake and potential interaction for the contra-rotating fan. The influ- ence of the blade row distance between the front and rear rotors and pressure fluctuations on the casing wall were investigated for the counter rotating fan with fan diameter D = 375 mm [3] [7]. On the other hand, the conventional de- sign method and the theory for the turbomachinery should be modified for small-sized axial fans because small-sized axial fans applied to electrical devices belong to extremely small size field in the turbomachinery [8]. Therefore, there is the strong demand to establish the design method for small-sized axial fans based on the internal flow. Then, the internal flow condition was investigated using the numerical models having different blade row distance L = 10 mm and 30 mm at the design flow rate [9]. Regarding the conventional axial flow fan, the relative velocity vectors and streamlines at off-design flow rate points with the deep stall condition were computed using the downstream flow resistance me- thod [10]. Unsteady flow in axial skewed fans was measured at off-design condi- tions using a hot-wire anemometer, to investigate the effect of sweep on the performance and flow condition [11]. On the other hand, the internal flow con- dition of the contra-rotating axial flow fan at off-design flow rate point is not known well. Then, the internal flow condition at partial flow rate was investi- gated by a pitot-tube and numerical analysis, and it was clarified that the back flow associated with the tip leakage flow occurred at the inlet tip of both front and rear rotors [12]. It is difficult to measure the internal flow condition at low flow rate and there is no literature related to the internal flow condition of the contra-rotating small sized axial fan at low flow rate. Therefore, the internal flow condition at the low flow rate was investigated by the numerical analysis.
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Numerical Investigation on Vortex Structure and Aerodynamic Noise Performance of Small Axial Flow Fan

Numerical Investigation on Vortex Structure and Aerodynamic Noise Performance of Small Axial Flow Fan

should be produced under the conditions of existence of the vortex when the flow rate is very low. Sound was only generated in the flow field with the region of vor- tices changed over time. OU-yang Hua et al. [5] studied the flow field of low speed axial fans with different set- ting angle by PIV and CFD simulation, and analyzed the relationship between inner flow field of fan and noise radiation based on vortex sound theory of low speed homentropic flow, and then predicted aerodynamic noise of fan. It was shown that aerodynamic noise of low speed homentropic flow was mainly induced by stretch and breakdown of vortex in flow. To uniform inflow aerody- namic noise source of low speed axial fan was major caused by blade trailing edge vortex shedding and tip
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EXPERIMENTAL ANALYSIS OF TIP CLEARANCE AND CHORD LENGTH FOR OPTIMUM DESIGN OF AXIAL FLOW FAN IN AIR COOLED HEAT EXCHANGER

EXPERIMENTAL ANALYSIS OF TIP CLEARANCE AND CHORD LENGTH FOR OPTIMUM DESIGN OF AXIAL FLOW FAN IN AIR COOLED HEAT EXCHANGER

2.1 Propeller Fans:- They are used for high volume flow rate with lower pressure rise. These types of fans are cheaper in construction as compared to other fans and maximum efficiency carried out at deliver section of fan. Propeller fans are used in rooftop ventilation or as panel mounted on the well of structure. Even though, they operated in reverse direction in order to achieve ventilation application. They have low energy efficiencies as compared to other axial flow fans as well as noisy in operations. They are directly driven by motor with the help of belt to the hub.
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