Blade Surface Pressure Measurements on a Low Pressure Rise Axial Flow Fan

2021 ◽  
Author(s):  
Johan Van Der Spuy ◽  
Theodor Von Backstrom ◽  
Johannes Rohwer ◽  
Francois Louw
Keyword(s):  
Surface Pressure ◽  
Axial Flow ◽  
Pressure Rise ◽  
Low Pressure ◽  
Pressure Measurements ◽  
Blade Surface ◽  
Axial Flow Fan

Blade Surface Pressure Measurements on a Low Pressure Rise Axial Flow Fan

2020 ◽  
Author(s):  
Johannes Rohwer ◽  
Sybrand J. van der Spuy ◽  
Theodor W. von Backström ◽  
Francois G. Louw
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Surface Pressure ◽  
Static Pressure ◽  
Axial Flow ◽  
Pressure Rise ◽  
Test Facility ◽  
Pressure Measurements ◽  
Blade Surface ◽  
Axial Flow Fan

Abstract Fan performance characteristic tests of axial flow fans provide information on the global flow field, based on stable inlet flow field distribution. More information is often required on the local flow distribution existing in the vicinity of the fan blades under installed conditions. A 1.542 m diameter scale model of an axial flow fan, termed the M-Fan is tested in an ISO 5801, type A, test facility. The M-fan was specifically designed for low-pressure, high flow rate application in air-cooled or hybrid condensers. The scaled version of the M-fan was designed to have a fan static pressure rise of 116.7 Pa at a flow rate of 14.2 m3/s. Two specially constructed M-Fan blades are manufactured to conduct blade surface pressure measurements on the blades. The fan blades are equipped with 2 mm diameter tubes that run down the length of the fan blades in order to convey the measured pressure. Piezo-resistive pressure transducers, located on the hub of the fan, measure the static pressure distribution on the blades and the data is transferred to a stationary computer using a wireless telemetry setup. The blade pressure measurement setup is re-commissioned from a previous research project and its performance is qualified by testing and comparing to experimental results obtained on the B2a-fan. Excellent correlation to previous results is obtained. The experimental M-fan results are compared against results from a periodic numerical CFD model of a fan blade modelled in an ISO 5801, Type A test facility configuration. The experimental tests and numerical model correlate well with each other. The experimental blade surface pressure measurements have a minimum Pearson correlation to the numerically determined values of 0.932 (maximum 0.971).

The Design of a Large Diameter Axial Flow Fan for Air-Cooled Heat Exchanger Applications

2017 ◽  
Author(s):  
Michael B. Wilkinson ◽  
Johan van der Spuy ◽  
Theodor W. von Backström
Keyword(s):  
Flow Field ◽  
Large Diameter ◽  
Axial Flow ◽  
Pressure Rise ◽  
Design Procedure ◽  
Axial Flow Fan ◽  
Disk Model ◽  
Actuator Disk ◽  
Static Efficiency ◽  
Air Cooled Heat Exchanger

An axial flow fan design methodology is developed to design large diameter, low pressure rise, rotor-only fans for large air-cooled heat exchangers. The procedure aims to design highly efficient axial flow fans that perform well when subjected to off design conditions commonly encountered in air-cooled heat exchangers. The procedure makes use of several optimisation steps in order to achieve this. These steps include optimising the hub-tip ratio, vortex distribution, blading and aerofoil camber distributions in order to attain maximum total-to-static efficiency at the design point. In order to validate the design procedure a 24 ft, 8 bladed axial flow fan is designed to the specifications required for an air-cooled heat exchanger for a concentrated solar power (CSP) plant. The designed fan is numerically evaluated using both a modified version of the actuator disk model and a three dimensional periodic fan blade model. The results of these CFD simulations are used to evaluate the design procedure by comparing the fan performance characteristic data to the design specification and values calculated by the design code. The flow field directly down stream of the fan is also analysed in order to evaluate how closely the numerically predicted flow field matches the designed flow field, as well as determine whether the assumptions made in the design procedure are reasonable. The fan is found to meet the required pressure rise, however the fan total-to-static efficiency is found to be lower than estimated during the design process. The actuator disk model is found to under estimate the power consumption of the fan, however the actuator disk model does provide a reasonable estimate of the exit flow conditions as well as the total-to-static pressure characteristic of the fan.

scholarly journals Unsteady Pressure Measurements in a Rotating Centrifugal Impeller

1992 ◽  
Author(s):  
G. Roth
Keyword(s):  
Surface Pressure ◽  
Suction Side ◽  
Rotating Stall ◽  
Centrifugal Impeller ◽  
Pressure Measurements ◽  
Blade Surface ◽  
Pressure Transducers ◽  
Engine Order ◽  
Analysis Technique ◽  
Stable Operating

The design of a shrouded radial test impeller which enables the application of miniature pressure transducers inside the blades is presented. An explanation of the measurement and analysis technique is given. The results of suction side blade surface pressure measurements at several points of a performance line are presented. Two different types of diffuser rotating stall were detected. The pressure behaviour at impeller stall and surge inception is demonstrated. Furthermore, the periodic engine order blade surface pressure signals at a stable operating point are shown.

Improving Stall Margin by Using an Air-Separator for a Variable-Pitch Axial-Flow Fan

2004 ◽  
Author(s):  
Takahiro Nishioka ◽  
Shuuji Kuroda ◽  
Tadashi Kozu
Keyword(s):  
Axial Flow ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Axial Flow Fan ◽  
Clearance Ratio ◽  
Variable Pitch ◽  
Stall Margin ◽  
Operating Range ◽  
Exposure Ratio ◽  
Air Separator

An air-separator for extending the operating range of a variable-pitch axial-flow fan has been developed. It has a circular-are outer casing, a part of which forms the guide vane at the inlet of the air-separator. To obtain a wide operating range and to minimize penalties in terms of efficiency and noise, the influence of exposure and clearance ratios at various stagger-angle settings for rotor blades in low-speed and high-speed axial flow fans was experimentally investigated. Flow distributions and pressure fluctuations downstream of the rotor were also measured in order to investigate the influence of the air-separator on rotating stall. The distributions and fluctuations suggested that the air-separator decreased the blockage effect near the rotor tip and suppressed the rotating stall. Moreover, stall-margin and pressure-rise improvements were independent of the clearance ratio. These improvements depended on the exposure ratio and stagger-angle settings for the rotor blades. The fan efficiency for the air-separator also depended on the exposure ratio. In addition, the efficiency had the opposite tendency to the stall-margin and pressure-rise improvements. In contrast, the noise for the air-separator was independent of the exposure ratio and decreased as the clearance ratio increased. For the optimum combination of the exposure and clearance ratios, the stall-margin and pressure-rise were improved by over 20% with minimized penalties in terms of efficiency and noise. It is concluded from these results that the developed air-separator can provide a wide operating range for a variable-pitch axial-flow fan.

Design and Flow Analysis of a Rim-Driven Hub-Less Axial Flow Fan

2021 ◽  
Author(s):  
Hanqing Yang ◽  
Yijun Wang ◽  
Jinju Sun ◽  
Bangyi Wang ◽  
Youwei He ◽  
...  
Keyword(s):  
Design Method ◽  
Flow Behavior ◽  
Tangential Velocity ◽  
Axial Flow ◽  
Pressure Rise ◽  
Low Noise ◽  
Flow Mechanism ◽  
Axial Flow Fan ◽  
Flow Area ◽  
Overall Performance

Abstract Rim-driven hub-less fans have newly emerged as the most compact type of axial flow fans, which permits flexible configuration arrangements, large relative flow area and low-noise level operation. However, previous publications on rim-driven axial flow fans are rarely found in the open literature, and the flow mechanism and design principle of such promising fans haven’t yet been well-understood and established. This paper has been focused on a preliminary study of the rim-driven axial flow fan design and flow mechanism. A design method of the rim-driven fans is proposed on the basis of the isolated airfoil scheme and the variable circulation rule. It is further incorporated into a FORTRAN code and suited for designing the rim-driven hub-less fans of low-pressure levels. For validation purpose, a conventional hub-type fan is redesigned with the developed method and its flow behavior and overall performance are investigated numerically. A parametric study on the designed fan is further conducted respectively for the tangential velocity difference at mean span, circulation exponent and sweep angle and their influence on the fan flow characteristics and overall performance are explored and highlighted. On such a basis, the developed design method for the rim-driven axial flow fan is further improved. In comparison with the conventionally designed fan at identical rotating speed, significant comprehensive gains are arising from the redesigned fan of hub-less configuration: the overall pressure rise and static pressure efficiency is enhanced respectively by 6.2% and 11.5%, whereas the diameter of the fan is reduced by 12.5% simultaneously. It is demonstrated that the rim-driven hub-less configuration is promising for the enhancing the fan overall performance with even reduced dimensions.

1221 Frequency Analysis of Pressure Fluctuation on Blade Surface of Small Axial Flow Fan

2013 ◽  
Vol 2013.50 (0) ◽  
pp. 122101-122102
Author(s):  
Kiyoshi KAWAGUCHI ◽  
Fuminobu WATANABE ◽  
Kenji OOE ◽  
Daisuke WATANABE
Keyword(s):  
Frequency Analysis ◽  
Pressure Fluctuation ◽  
Axial Flow ◽  
Blade Surface ◽  
Axial Flow Fan ◽  
Small Axial Flow Fan
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