Study and Analysis of the Filter Clogging Effect on the Pressure Losses of an Axial Fan (original) (raw)
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The Influence of the Level of the Flow Path Blockage at the Inlet on the Fan Characteristics
Proceedings of the 9th International Conference on Simulation and Modeling Methodologies, Technologies and Applications, 2019
The paper presents the results of numerical simulation of the effect of flow nonuniformities at the engine inlet on the working process of the engine fan. Flow nonuniformities is created by pushing the interceptor into the flow part of inlet device like as it is often done during field tests. The authors have created a numerical model capable of considering non-stationary processes in the fan using nonlinear harmonic analysis. As a result, qualitative and quantitative estimates were obtained of the influence of overlapping of the inlet duct by the interceptor on the main parameters of the fan workflow. It is shown that the more the duct is blocked, the more its parameters are deteriorated. Moreover, the deterioration is not linear, but according to the dependence of the 2nd order. NOMENCLATURE G mass flow rate of the working fluid, kg/s; p* total pressure, Pa; Т* total temperature, K; n rotor speed, %; m bypass ratio; efficiency; Y+ non-dimensional wall distance; flow angle, degree; LPC low pressure compressor; RW rotor wheel; GV guide vane; NLH nonlinear harmonic analysis. Note. The flow angles in this research are measured from the aerofoil cascade front.
Effect of Suction Slot Location and Width on the Performance of Centrifugal Fan
S. A. Beskales, 2023
Blade slots are known to reduce the noise and improve flow behavior and steadiness in centrifugal fans. The present work considers an unsteady Computational Fluid Dynamic (CFD) study to investigate the effectiveness of slot location and width on the performance and flow field inside the centrifugal fan blade passages. The computer program, Fluent 19, is used and the 3D fan model is validated by comparing its results with those of earlier researchers. The aim of the present study is to find the best slot location and appropriate slot width at that location. The flow pattern is then analyzed and simulated with no slot and with a slot at six different radial locations; namely S1, S2, S3, S4, S5, and S6 with fixed slot width W of 2.5 mm. The computationally generated characteristics of unsteady flow demonstrated that although cut slots at all locations on the fan blade from the hub to the shroud has a negative influence on the centrifugal fan efficiency as well as the static pressure rise compared with the fan without slot, the slots added at S3 i.e. near the midpoint of the blade span gives the highest fan efficiency and largest increase in static pressure. Slots at S3 suppress secondary flow at the blade passages and push it to the blade tip. Additionally, streamlines and velocity distributions in impeller passages and over the blade surfaces (pressure and suction sides) validated the slots' benefits. Computations width different slot width; namely 1.5 mm, 3.5 mm, and 5 mm are carried out to find the best slot location and width at the best slot location S3. At the optimal efficiency point, the calculated performance of the employed fan with slot location S3 and 2.5 mm width, showed a 2.7 % increase of efficiency and 1.5% increase in static pressure rise as compared to fans with slot at S1 with same width of 2.5 mm. However, it showed a positive impact on the boundary layer buildup and flow separation over the blade suction side for the impeller studied .
Experimental Investigation on Aerodynamic Characteristics of an Axial Flow Fan
The prime objective of this work is to determine the relationship between the mechanical and aerodynamic characteristics of the fan when the blade position is default and when it is changed and to find out which position gives optimum output at given power and given working conditions and according to the change of environment. In this experiment, the aerodynamic characteristic of an axial flow fan is going to be determined by measuring the static and total pressures in the suction and discharge sides of the fan for various flow rates. In this experiment, for different blade angle, flow velocity is measured and relationship between the change of blade angles and the flow velocity are plotted
COMPARATIVE ANALYSIS OF PRESSURE MEASUREMENTS IN DUCTED AXIAL FAN
The paper deals with experimental investigation and comparative analysis of pressure measurements in ducted axial fan. Experiments were carried out to investigate the nature of pressure variations in a ducted axial fan at different throttle positions as a function of rotor speed employing both manometer and pressure sensors. Quantitative analyses of the magnitudes of pressures measured by a manometer as well as a pressure sensor are examined and various graphs have been plotted. The percentage errors of pressure level have been determined
Performance of large fan-filter units for cleanroom applications
Building and Environment, 2007
Fan-filter units (FFUs) are widely used in clean space to re-circulate and remove particles out of the airflows directed to cleanrooms or minienvironments. Energy and aerodynamic performance of FFUs may largely influence both energy efficiency and effectiveness in contamination control in the cleanroom design, qualifications, and operation. This article presents laboratory-measured performance of seven relatively new and large FFUs, with a section size of 122-cm  122-cm, or 4-ft  4-ft. In addition, this article includes a comparison of the performance of these large FFUs with that of smaller, 122-cm  61-cm (or 4-ft  2-ft) FFUs that were previously tested. The comparison was based upon a set of performance metrics such as total pressure efficiency (TPE) and energy performance index (EPI). This article found that there were wide variations in the energy performance of FFUs, and that using a consistent evaluation method can generate comparable FFU performance information. When operating at the maximal setting of speed control dials used to control their respective fan-wheel speeds, the larger units in this study tended to be more energy efficient than their smaller counterparts. The energy efficiency level of the same unit may vary considerably, depending on actual operating conditions such as airflow speeds and pressure rise across the units. Furthermore, this article provides recommendations for further investigations to improve energy efficiency of FFU applications.
Analysis and Simulation of Axial Fan Using CFD
The aim of this study is to analyze a nine-bladed axial fan, standard specifications are used to generate a framework of axial fan efficiency. Using currently available CFD programs, the research is carried out in an efficient manner. At the inlet, results were obtained using typical boundary conditions, with fluid conditions at the outlet. The results showed a higher pressure of 381.62 Pa and a maximum velocity of 37.5 m/s at the outlet for these conditions. These results can also be used to compare the performance of a nine-blade axial fan with a nineand twelve-blade axial fan.
Experimental Thermal and Fluid Science, 2011
The purpose of this work is to study the effects of blade thickness on the performances of an axial-flow fan. Two fans that differ only in the thickness of their blades were studied. The first fan was designed to be part of the cooling system of an automotive vehicle power unit and has very thin blades. The second fan has much thicker blades compatible with the rotomoulding conception process. The overall performances of the fans were measured in a test bench designed according to the ISO-5801 standard. The curve of aerodynamics characteristics (pressure head versus flow-rate) is slightly steeper for the fan with thick blades, and the nominal point is shifted towards lower flow-rates. The efficiency of the thick blades fan is lower than the efficiency of the fan with thin blades but remains high on a wider flow-rate range. The mean velocity fields downstream of the rotors are very similar at nominal points with less centrifugation for the thick blades fan. Moreover, the thick blades fan maintains an axial exit-flow on a wider range of flow-rates. The main differences concern local properties of the flow: Phase-averaged velocities and wall pressure fluctuations strongly differ at the nominal flow-rates. The total level of fluctuations is lower for the thick blades fan that for the thin blades fan and the spectral decomposition of the wall fluctuations and velocity signals reveal more harmonics for the thick blades fan, with less correlation between the different signals. For this kind of turbomachinery, the use of thick blades could lead to a good compromise between aerodynamic and acoustic performances, on a wider operating range.
Modification of Axial Fan Flow by Trailing Edge Self-Induced Blowing
Journal of Fluids Engineering, 2009
Axial fans often show adverse flow conditions at the fan hub and at the tip of the blade. The modification of conventional axial fan blade is presented. Hollow blade was manufactured from the hub to the tip. It enables the formation of self-induced internal flow through internal passages. The internal flow enters the passage of the hollow blade through the opening near the fan hub and exits through the trailing edge slots at the tip of the hollow blade. The study of the influence of internal flow on the flow field of axial fan and modifications of axial fan aerodynamic characteristics is presented. The characteristics of the axial fan with the internal flow were compared to characteristics of a geometrically equivalent fan without internal flow. The results show integral measurements of performance testing using standardized test rig and the measurements of local characteristics. The measurements of local characteristics were performed with a hot-wire anemometry and a five-hole prob...
2010
The study of Aerodynamic performance of axial-flow fans was carried out. Two fans that differ only in the thickness of their blades were studied. The first fan (Fref), which is the reference, was designed to be part of the cooling system of an automotive vehicle power unit and has conventional thin blades. The second fan (Ftck) has much thicker blades compatible with the rotomoulding conception process that generates only hollow parts with large edge radius. The global performances of the fans were measured in a test bench designed according to the ISO-5801 standard. The curve of aerodynamics characteristics (pressure head versus flow rate) is slightly steeper for the fan with thick blades, and its efficiency is lower than the efficiency of the fan with thin blades. To go further in the comparison, we also studied the wall pressure fluctuations at the casing wall in another normalized test bench, for two flow rates corresponding to the maximum efficiencies of the two fans. The total...
International Journal of Rotating Machinery, 2011
The flow field at the rotor exit of a low aspect ratio axial flow fan for different tip geometries and for different flow coefficients is measured in the present study. The following configurations are tested: (1) rotor without partial shroud, designated as rotor (wos), (2) rotor with partial shroud, designated as rotor (ws), and (3) rotor with perforated (perforations in the shape of discrete circular holes) partial shroud, designated as rotor (wps). From steady state measurements, the performance of rotor (wps) is found to be the best. Both the rotors with partial shrouds have stalled at a higher flow coefficient compared to that of rotor (wos). From periodic flow measurements, it is concluded that the low velocity region near the tip section is considerably reduced with the use of partial shrouds with perforations. The extent of this low velocity region for both rotor (wos) and rotor (wps) increases with decreasing flow coefficient due to increased stage loading. This core of low...