A study on the half-ducted axialflowfan designed by a diagonal flowfan de- sign method was conducted. The rotor which has NACA65 blades was de- signed, calculated numerically, manufactured and tested experimentally. As a result of the design and CFD, the meridional streamline and three distribu- tions of the meridional, tangential and radial velocity at inlet and outlet go well as designed values of the half ducted fan. On the other hand, the values of the meridional velocity and the tangential velocity are little smaller than the design values at the hub side of the radial distribution. The improvement of the design is prospected for this point, that is, the approach between the de- sign value and the actual flow is prospected if the tangential velocity is as- signed small at hub and is assigned large at the tip so as to accord the actual flow in the vortex design of the rotor blade. Then the designed half-ducted rotor with four NACA65 blades was fabricated by a three-dimensional printer and tested in the wind tunnel in order to validate the half-ducted design me- thod. For the comparison between the design values and the experimental values at the designflow rate coefficient of φ = 0.264, the experimental values of the pressure rise coefficient ψ and the efficiency η are rather small than the design values, while the experimental value of the torque coefficient τ is al- most the same as the design value. However, the experimental value of ap- proximately 0.45 of the maximum efficiency is comparably large value consi- dering for the limitation of the situation of half-ducted. For the comparison between the experimental values and the CFD values at φ = 0.264, the CFD values are almost the same values as the experimental values for all the values of ψ , τ and η . In addition, the tendencies of the CFD values when the flow rate coefficient changes are almost similar as the experimental tendencies, though the flow rate coefficient for the CFD values when ψ or η takes the peak value shifts toward larger flow rate. For the case at rotor outlet at φ = 0.264, two How to cite this paper: Kaji, A., Kinoue,
Thiart and Von Backström (1993) showed that the o design performance of an axial ow fan could be reasonably estimated by means of a simplied nu- merical model incorporated into a computational uid dynamics (CFD) code. A similar numerical model to that used by Thiart and Von Backström (1993) was used by Meyer (2005), who performed a numerical investigation of a sy- stem of two banks of air-cooled heat exchangers. Meyer (2005) shows that the large performance loss in the edge fans is due to ow separation occurring around the fan inlet bellmouth, while losses in fans further from the edge of the heat exchanger unit are due to oblique ows at the fan inlets. A comparable study by Bredell et al. (2006) investigated the eect of cross-ow and platform height on the performance of two dierent fans. Bredell et al. (2006) attributed the drop in volume ow through the fans under o design conditions to a com- bination of factors such as increased inow losses, o axis ow conditions and poor distribution of air ow into the fan resulting in blade stall. Owing to the complex nature of the ndings and the fact that a simplied numerical model was used, further insight was not possible. Another nding made by Bredell et al. (2006) is that the B-fan of Bruneau (1994) with an optimised hub-to-tip ratio outperformed the more basic A-fan, which had a smaller hub-to-tip ra- tio, under distorted ow conditions. An extensive numerical and experimental investigation by Van der Spuy (2011) provides further insight into the sen- sitivity of fans to distorted inows. Using a number of numerical models as well as experimental investigations of Van der Spuy (2011) investigated the performance of several fans, designed to the same operating point, subjected to distorted inow conditions. It was found that distorted inows reduced the volume ow rate through a given fan, potentially resulting in the fan opera- ting outside its design operational range. This potentially leads to fan stall in some cases, however Van der Spuy (2011) indicates that local reductions in ow rate through the fan blades due to factors such as ow separation at the inlet may be more severe. It was also found that fans with higher solidities and larger hub-to-tip ratios were less sensitive to distorted inows in terms of volumetric eectiveness, however these fans were not necessarily the most ecient in terms of power consumption.
A B S T R A C T
The objective of this paper is the numerical study of the flow through an axialfan and examining the effects of blade design parameters on the performance of the fan. The axialfan is extensively used for cooling of the electronic devices and servers. Simulation of the three-dimensional incompressible turbulent flow was conducted by numerical solution of the (RANS) equations for a model. The SST- k- ω and k-ε turbulence models are applied in the simulations which are done using CFX software. The comparison between available experimental data and simulation results indicates that the SST k-ω model gives more accurate results than the k-ε model. The results also show that in separation regions and vortices, the pressure will decrease. Hub area and blade root contain large vortices . The effects of changes in the blade geometry and the number of blades on the fan performance are studied in detail.
Use of Fossil Fuels in Power Generation has its adverse environmental impact. And due to growing population there is a scarcity of Fossil Fuels in today’s world. To cope up with this problem this paper suggests the Design of D. C. Operated Vacuum Cleaner using AxialFlowFan, which is capable of producing a Suction Pressure of 0.17 Bar. And it is more efficient in Cleaning and has less D. C. Power Consumption. This Vacuum Cleaner is wireless leading to better approach in cleaning the floor. As this Vacuum Cleaner is Eco-Friendly, looking forward to use a cleaner source of energy for the betterment of mankind, planet earth and environment.
Mahajan Vandana N, Shekhawat Sanjay P, “Analysis of Blades of AxialFan Using ANSYS”, ed. E. Frollini, A.L. Leão and L.H.C. Mattoso, 159-201, 2000, San Carlos, Brazil: Embrapa, USP-IQSC, UNESP.
Witt & Sohn Ag “Stall and parallel operation” ,83 (12), Journal of Applied Engineering Science,pp.2634-2643.
Ing.Robin Poul, Doc.Ing Daniel Hanus “Design Otimisation and technology of carbon composite axialflowfan rotor blade of light aircraft propulsion system”, International congress of the aeronautical sciences.
7. Stefano Bianchi, Alessandro Corsini, Anthony G. Sheard researched about one of the critical problems of occurrence of loss of energy in fans i.e. stall. They wrote a research paper in which critical reviews of stall control techniques in industrial fans were included.
The basic objective was to understand the key physical phenomena that occur with stall inception that is critical to alleviate stall by design or through active or passive control methods. The methods and prospects for early stall detection to complement control systems with a warning capability.
CHAPTER 1. INTRODUCTION 2 An ACC consists of a series of heat exchanger bundles which receive steam from the turbine exhaust via a common steam header. The steam ﬂows through ﬁnned tube heat exchanger bundles which reject heat to the ambient air, al- lowing the steam to condense. Large axial ﬂow fans, approximately 10 m in diameter are driven through an electric motor and gearbox assembly. The fans force cool ambient air through the heat exchanger bundles. The steam condensate is collected in the condensate ducts at the bottom of the ACC. One drawback of forced draught ACHEs is their reduced thermodynamic eﬃ- ciency due to their higher condensing pressure, compared to wet-cooled heat exchangers. Another drawback is the relatively high parasitic energy consump- tion of the axial ﬂow fans when compared to wet cooled heat exchangers. The Matimba coal-ﬁred power plant has 6 x 665 MW(e) units and requires ap- proximately 65 MW to power the axial ﬂow fans in the ACC system at full load (Van der Spuy, 2011). One way of reducing this power loss is to imple- ment more eﬃcient axial ﬂow fans. Experimental data on the operational fan performance can be used to analyse and further improve existing fan designs. Fan performance characteristic tests (fan static pressure and eﬃciency curves) provide information on the global ﬂow ﬁeld, based on stable inlet ﬂow ﬁeld dis- tributions. These tests usually require large test facilities adhering to industry speciﬁc standards. When testing axial ﬂow fans, more information is often re- quired on the local ﬂow distribution existing in the vicinity of the fan blades. Information concerning the local ﬂow ﬁeld could prove to be vital in fandesign considerations (e.g. ﬂow distribution, local lift and drag performance charac- teristics), better understanding of installed fan performance under distorted inﬂow conditions or for numerical validation of speciﬁc/localized regions across the fan blade.
I. I NTRODUCTION
An axialfan is a type of a compressor that increases the pressure of the air flowing through it. The blades of the axialflow fans force air to move parallel to the shaft about which the blades rotate. In other words, the flow is axially in and axially out, linearly, hence their name. The design priorities in an axialfan revolve around the design of the propeller that creates the pressure difference and hence the suction force that retains the flow across the fan. The main components that need to be studied in the designing of the propeller include the number of blades and the design of each blade. Their applications include propellers in aircraft, helicopters, hovercrafts, ships and hydrofoils.
Oday I. Abdullah, Josef Schlattmann, et al  In this paper the finite element method has been used to determine the stresses and deformations of an axialfan blade. Three dimensional, finite element programs have been developed using eight-node super parametric shell element as a discretization element for the blade structure. All the formulations and computations are coded in Fortran-77. This work was achieved by modeling the fan blade as a rotating shell. The investigation covers the effect of centrifugal forces on stresses and deformations of rotating fan blades. Extensive analysis has been done for various values, speed of rotation, thickness, skew angle, and the effect of the curvature on the stress and deformation. The numerical results have shown a good agreement compared with the available investigations using other methods.
Because of being limited by the methods of numerical simulation and experiment at that moment, the applica-
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.  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.
4.1 Experimental Setup 4.1.1 Vacuum Chamber
The vacuum chamber utilised during the course of the experimentation was purpose built for the fan blade under investigation and can be seen in gure 4.1. It consists of a 220 mm outer diameter pipe, which is 4 mm thick and 800 mm long. This pipe has had a pair of square anges welded to each end, which have been laser-cut to t over the pipe. This welded assembly, along with a pair of laser-cut end-caps and a number of seals, forms the vacuum chamber component of the experimental setup. It should be noted that the pipe in question was selected due to its inner diameter of 212 mm, which was wide enough to house the fan blade under investigation. The thickness of the pipe was not a pivotal factor in the design process, as the chamber was not intended to be a positive pressure vessel. The thickness of the pipe is a direct result of the internal diameter requirement, but it should be noted that a heavy setup was desired from the outset of the design process. It was hypothesised that by increasing the mass of the experimental setup, its resulting inertia would prohibit movement during the free vibration test.
Lingen Chen et al. , 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.
1,2,3 Geethanjali College Of Engineering & Technology
Email: 1 firstname.lastname@example.org, 2 email@example.com
An axialflow 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 axialflow 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 axialflow 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.
publications introducing the term “synthetic jet”: James et al. , Smith and Glezer .
Possibilities of SJs for an active flow control in turbomachinery were investigated, and a few relating publications focusing on low and high speed axial compressors have recently appeared, e.g. Kefalakis and Papailliou , Zheng et al. . The actuation can efficiently enhance momentum transport in the unstable boundary layer. Various locations of the actuation were investigated – note a very effective incorporation of the actuators into the blades with the flush-mounted operating orifices, Culley et al., . However, the penalty of this variant is an essential complication of the construction. Obviously, more feasible is to design actuation from channel sidewalls, as was investigated with the two-dimensional blade cascades, e.g. by Matějka et al.  and, more recently, by Zander et al. . This experimental investigation focused on a large scale, highly loaded compressor cascade, equipped with 30 SJ actuators (!) mounted to the sidewalls and on the blade suction side surface. They concluded a total pressure loss reductions of nearly 10% resulting from the SJ actuation.
In general, there are two different kinds of work to study the stall inception in compressors. One is to describe the compressor stability as an eigenvalue problem, while the stability can be judged by the imaginary part of the corresponding eigenvalues. The other is to directly solve Euler or Navier-Stokes equa- tions as an initial boundary value problem to obtain the information related to the inception condition [5-9] . The latter’s advantage is that this type of work can include the effect of more aerodynamic and geometrical parameters on the physical phenomena involved than the eigenvalue approach. However, there are no common rules to be followed about how to introduce the initial perturbations outside or inside the compu- tational domain to stimulate the stall inception or precursor. Therefore whether or not one can obtain a rapid and reliable result about the stall inception along the way will strongly depend on researcher’s experience and an affordable computational cost to a great extent. On the other hand, it is noted that for a dynamic system, its stability will depend on the response to a small perturbation outside the system. Mathematically, what one should do for this kind of analysis is to solve the corresponding eigenvalue equation in order to judge whether the system is stable or not. In fact, we can see that most of earlier work in the studies of the stall inception was to establish various eigenvalue models. Besides, the development of eigenvalue models in a compressible system has experienced a different stage since the 1970s. Nenni and Ludwig  extended the channel flowtheory presented by Sears  so as to include the effects of more aerodynamic and geometrical parameters of compressor rotors. Their work also resulted in an analytical expression for the inception condition of rotating stall. The work was soon extended to two- dimensional compressible flow case but no relevant numerical results
recirculation, crosswinds, ACC’s heat exchanger fouling and high dry-bulb temperature increases the turbine back pressure and produces a reduction of the steam turbine power output and this leads to an underperforming cooling system and requires lower the power output setting of the power station. One major function of the ACC is to produce a vacuum from the condensation of steam. Thus, requires the ACC systems to be monitored in conjunction with the other subsystems of the PowerStation. Furthermore, the electrical motors that drive the fans in the ACC are also responsible for parasitic power consumption of the power station, which must also be controlled to increase the powers station’s power output. Bruneau (1994) developed a rotor-only ducted axialflowfan, called the B2-fan. The B2-fan was specifically designed for use in an ACC. Due to problems related to reverse flow in the hub area of existing fans and the effect of distorted inlet airflow on fan performance, an issue highlighted by Venter (1990), a free vortex design was chosen for the B2-fan. The B2-fan was tested in the BS 848 test facility by Bruneau (1994) and subsequently Wilkinson and Van der Spuy (2015). The same B2-fan was used in this research.
A comprehensive aerodynamic treatment of ducted axialflow fans has been presented in the present work. Airfoil and the blade so designed are analysed using CFD software. The main emphasis will be on improvement of efficiency and the system performance.
Fans are a kind of equipment where we can use engineering strategies and optimize the energy consumption without effecting their efficiency. They are mainly being used for ventilation and cooling purposes at industrial plants. To cool a kiln-shell used in cement plant needs a fan with specific speeds which works for given site conditions. Whether it may be a blower or fan which is classified as an industrial fan, selection of a fan and design of impeller needs a keen study of rotor blade design which is majorly based on velocity components. The blade may be of simply a plate with camber angles or an aerofoil shape. Research is suggesting that replacing the curved camber plate with the aerofoil blade may produce almost identical performance but which results in the considerable increase in the structural strength of the blade.
Received September 11, 2012; revised October 25, 2012; accepted November 4, 2012
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 axialflowfan 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.