Effect of Rotational Velocity and Blade Angle of Attack on Mass Flow Rate in an Axial Fan at a Fixed Hub to Tip Ratio

2008 ◽  
Author(s):  
Mohammad J. Izadi
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Velocity ◽  
Angle Of Attack ◽  
Maximum Flow ◽  
Maximum Mass ◽  
Blade Angle ◽  
Axial Fan ◽  
Very High

In this investigation an attempt is made to find the best rotational velocity and the best angle of attack of a flat blade at a fixed hub to tip ratio for a maximum mass flow rate in an axial fan in a steady and turbulent conditions. In this study the blade angles are varied from 10 to 80 degrees and the rotational velocity is varied from 500 to 2500 RPM (50 to 200 rad/sec) for a number of blades from 2 to 6, at a fixed hub to tip ratio. The results show that, the maximum flow rate is achieved at the blade angle of attack of about 45 degrees when the number of blades is set equal to 4 at most rotational velocities. The numerical results show that as the rotational velocity increased, the mass flow rate increased, but at very high rotational velocities the mass flow rate remained constant.

Effect of Blade Angle of Attack and Hub to Tip Ratio on Mass Flow Rate in an Axial Fan at a Fixed Rotational Speed

2008 ◽  
Author(s):  
Mohammad J. Izadi ◽  
Alireza Falahat
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Angle Of Attack ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Maximum Mass ◽  
Blade Angle ◽  
Axial Fan

In this investigation an attempt is made to find the best hub to tip ratio, the maximum number of blades, and the best angle of attack of an axial fan with flat blades at a fixed rotational speed for a maximum mass flow rate in a steady and turbulent conditions. In this study the blade angles are varied from 30 to 70 degrees, the hub to tip ratio is varied from 0.2 to 0.4 and the number of blades are varied from 2 to 6 at a fixed hub rotational speed. The results show that, the maximum flow rate is achieved at a blade angle of attack of about 45 degrees for when the number of blades is set equal to 4 at most rotational velocities. The numerical results show that as the hub to tip ratio is decreased, the mass flow rate is increased. For a hub to tip ratio of 0.2, and an angle of attack around 45 degrees with 4 blades, a maximum mass flow rate is achieved.

Evaluation of Effects of Different Design Parameters on Axial Fan Performance Using CFD

2015 ◽  
Author(s):  
Racheet Matai ◽  
Savas Yavuzkurt
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Chord Length ◽  
Design Parameters ◽  
Axial Fan ◽  
Blade Length ◽  
Resistor Networks ◽  
Mass Flow Rates

The performance of an industrial fan was simulated using CFD and results were compared with the experimental data. The fan is used to cool a row of resistor networks which dissipate excess energy generated by regenerative power in an inverter application. It has a diameter of 24 inches (0.6096m) and rotates at different speeds ranging from 2500 to 3900 RPM depending on the requirements. CFD simulation results were also verified by simulating performance of the same fan at different speeds and comparing the results with what was expected from fan affinity laws. The CFD results matched almost exactly (with ∼0.2% difference for pressure at a given flow rate) with the performance being predicted by the affinity laws. The effect of variation of different parameters such as the blade length, number of blades, and blade chord length was studied. Increasing the blade length at the same RPM increased the mass flow rate (by ∼17%) for the same pressure. Increasing the chord length while keeping the same number of blades, at a given RPM, made the performance curve (pressure versus flow rate, i.e. PV curve) steeper and blades stalled at a higher mass flow rate (8.77 kg/sec compared to the previous 8.44 kg/sec). For the same total blade surface area, less number of blades with longer chords stalled at lower mass flow rates (9.22 kg/sec for a 33% shorter chord and 36 blades compared to 8.3 kg/sec for the original rotor which had 24 blades).

Capillary trees for passive pumping water

2021 ◽  
Author(s):  
Xuewei Zhang ◽  
Sylvie Lorente
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Flow ◽  
Search Algorithm ◽  
Geometrical Parameters ◽  
Maximum Mass ◽  
Capillary Flows ◽  
The Impact ◽  
Fixed Network

Abstract Capillary flows are an attractive feature for passive water harvesting as they require no external driving force to pull the fluid out within the capillary network. Here we analyze the architecture of capillary flow networks in steady state, and the impact of the network morphology on the maximum mass flow rate that can be extracted for a fixed network volume and fixed network footprint. We develop a search algorithm to test the possible location of all the junction and bifurcation nodes and the changes in diameter ratios with the objective of obtaining the maximum mass flow rate from the network. We define the Capillary Strength CS as a local indicator to determine the geometrical parameters of each conduct that allow to sustain the overall mass flow rate. It is shown that the diameter ratio of connected tubes for maximum mass flow rate depends on the distance from the network outlet, and therefore does not follow the Hess-Murray’s law. The superiority of dendritic architectures in the roots and canopy branches of the capillary trees is demonstrated.

Efficiency Improvement of Industrial Fans if Operating at Off-Design Modes

2019 ◽  
Vol 7 (3) ◽  
pp. 43-51
Author(s):  
Глеб Замолодчиков ◽  
Gleb Zamolodchikov ◽  
Р. Тумашев ◽  
R. Tumashev ◽  
Н. Щеголев ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Efficiency ◽  
Operating Mode ◽  
Rotor Blades ◽  
Aerodynamic Load ◽  
Axial Fan ◽  
Performance Factor ◽  
Wide Range

This paper’s aim is enhancement of efficiency for fans adjusting by turn of rotor blades. A high load axial fan and a fan with decreased rotor’s pitch chord ratio by reduction of blades number were investigated. Have been performed tests of the fan with design characteristics as follows: theoretical head coefficient Ht = 0,3, mass flow rate Ca = 0,4, hub’s relative diameter ν = 0.6, and with blades, graded on the law of permanent circulation. The area of effective adjustment was estimated by the performance factor value η* ≥ 0,8. When changing the stagger angles in a wide range from 26° to 70°, the area of highly economical work was in variation ranges 0,26–0,78 for the mass flow rate Ca , and 0,24–0,5 for the theoretical head coefficient Ht accordingly. Tests of fans with a reduced blades number in the rotor (12 instead of 16 for the original fan) has showed that under the same stagger angles the fan’s high-efficiency operating mode is approximately in the same range of Ca variation at slightly reduced values of theoretical head coefficient. Maximal performance factor has increased on 2.5%. Decreasing the number of rotary blades, simplifying the turning mechanism and reducing the weight are possible in the design of fans with increased values of aerodynamic load coefficients.

scholarly journals Sailing into Wind Is Explained by Newtonian Mechanics Based on The Mass-Flow Rate

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Nicholas Landell-Mills
Keyword(s):  
Fluid Mechanics ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Relative Velocity ◽  
Angle Of Attack ◽  
Coanda Effect ◽  
Newtonian Mechanics ◽  
Coandǎ Effect

The physics of sailing into the wind can be explained using Newtonian mechanics based on the mass flow rate. The sail re-directs a mass of air each second (m/dt) towards the boat’s stern, at a relative velocity (dv) that depends on the apparent wind. The re-directed airflows push against the otherwise undisturbed apparent wind to create a backward force (i.e. Force = ma = m/dt × dv). The reaction generates an equal and opposite forward force that pushes the boat ahead. There are two separate airflows as the sail re-directs the wind on the sail’s windward and leeward sides. The leeward airflow relies on the Coanda effect and is sensitive to the sail’s angle-of-attack (AOA). This approach provides new and valuable insights on sailing into the wind. However, it is a very different approach compared to the current explanations of sailing into the wind, described by fluid mechanics and vector-based solutions.    

Investigations on the Effect of Blade Angle on Ventilated Brake Disc Using CFD

2005 ◽  
Author(s):  
Kannan M. Munisamy ◽  
Hanan Mokhtar ◽  
Hasril Hasini ◽  
Mohd Zamri Yusof ◽  
Mohd Azree Idris
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Linear Trend ◽  
Brake Disc ◽  
Blade Angle ◽  
Flow And Heat Transfer

This paper presents the investigation on the effect of blade angle to the mass flow and heat transfer coefficient of a ventilated brake disc. Six different blade angle configurations are simulated using commercial computational fluid dynamics code, FLUENT. Important parameters such as mass flow rate of air through the ventilated blade and surface heat transfer coefficient are predicted and analyzed. Prediction shows reasonable estimation of mass flow rate and heat transfer coefficient on the disc brake. Linear trend is achieved on the mass flow and heat transfer coefficient as the vehicle speed increases. It is also concluded that the optimum mass flow and heat transfer coefficient are predicted at blade angle of 15°. The prediction provides an insight into the behavior of the air flow through the restricted passage of the brake disc design.

scholarly journals EXPERIMENTAL STUDY THE EFFECT ANGLE OF BLADE ON THE ELECTRICAL POWER OUTPUT OF PROPELLER PICOHYDRO TURBINE

2019 ◽  
Vol 18 (2) ◽  
Author(s):  
Abdullah Shalih ◽  
Purwadi Joko Widodo ◽  
Dwi Aries Himawanto
Keyword(s):  
Experimental Study ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Electrical Power ◽  
Blade Angle ◽  
Optimal Power ◽  
Test Parameters ◽  
Water Turbine ◽  
Electrical Power Output

<p><em>This study aimed to analyze the effect of angle of blade on the horizontal flow to the performance of the propeller water turbine. The experiments were performed using several test parameters including the angle of blade on the variation mass flow rate of water. With potential head 2 meters and variated turbine blade angle to achieved optimal power generated.  The result showed that the variation of angle of blade with 30<sup>0</sup> angles and 11.6 l/s mass flow rate of water was the best variation to improve the performance of the propeller water turbine. The best variation can generated 32 Watt of electric power.</em></p>

Hydrodynamic Efficiency Improvement of High-Specific-Speed Centrifugal Pump Impeller

2013 ◽  
Vol 467 ◽  
pp. 461-465 ◽  
Author(s):  
Chin Ting Yang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Efficiency ◽  
Maximum Flow ◽  
Performance Measurement System ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Frictional Loss ◽  
Specific Speed

The high-specific-speed centrifugal pumps are very common in industrial factory for transporting fluids all day long. However, oversized pumps with low performance still could meet the purpose of fluid transporting. The aim of this study was to reduce the existed commercial impeller energy consumption by optimizing the performance of impeller through CAE processes. The impeller model was first generated by BladeGen software and analyzed by CFX in Turbo-mode. The optimized model then exported to machine center to cut the precise aluminum mold. A regular sand die casting processes were used to manufacture the impeller. The original pump which only impeller was replaced with the new one was tested with performance measurement system again. The results show that when the mass flow rate between 40-90kg/s the CFD software predicted very well pump heads and efficiencies with experimental data, which was called optimized impeller. But around the minimum and maximum flow rate region, the recirculation flow between blades and frictional loss model used still need further investigation to shrink the difference. Compare to the original impeller, the optimized one had increased efficiency 6% at the mass flow rate of 80kg/s. Also the high efficiency region (nearby of BEP) of the new impeller had broadened 50%. And the maximum mass flow rate increased 13% than the original one.

scholarly journals Particle Lift Challenges and Solutions for Solid Particle Receiver Systems

2019 ◽  
Author(s):  
Joshua M. Christian ◽  
Jeremy Sment ◽  
Clifford K. Ho ◽  
Lonnie Haden ◽  
Kevin Albrecht
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Large Scale ◽  
Rotational Velocity ◽  
Cost Effective ◽  
Control Device ◽  
Test Facility ◽  
Variable Frequency Drive ◽  
Bucket Elevator

Abstract Particle receiver systems require durable, reliable, and cost-effective particle transport equipment. These lifts are critical pieces of equipment to transport the particles from the heat exchanger back into the receiver. There are challenges that must be overcome with any particle lift device including high temperatures (800°C), particle load and friction, and erosion from particle contact. There are several options commercially available for particle systems including a screw-type vertical elevator, bucket lift vertical elevator, and skip-hoist-style bulk vertical lifts. Two of the elevator types (screw and bucket) have been tested at the National Solar Thermal Test Facility (NSTTF) at Sandia National Laboratories (SNL) in Albuquerque, NM. The two elevators are currently in operation on the 1 MWth falling particle receiver at the Solar Tower. The screw-type elevator consists of a stationary internal screw with an outer casing that rotates about the screw. The frictional forces from the casing rotation drives the particles upward along the flights of the screw. The casing rotational velocity is variable which allows for mass flow rate control. Identified issues with the screw-type elevator include particle attrition, uneven loading at the inlet causes casing deflection, bearing deformation due to casing deformation, and motor stalling due to increased resistance on the casing. The SNL bucket elevator is rated for temperatures up to 600 °C and consists of steel buckets and a steel drive chain capable of lifting particles at a rate of 8 kg/s. Identified issues with the bucket type elevator include discrete (non-continuous) discharge of the particles and a non-adjustable flow rate. A skip hoist type elevator has been studied previously and seems like the most viable option on a large scale (50–100MWth power plant) with a non-continuous particle discharge. Different control scenarios were explored with the variable frequency drive of the screw-type elevator to use it as a particle-flow control device. The objective was to maintain the feed hopper inventory at a constant value for steady flow of particles through the receiver. The mass flow rate was controlled based on feedback from measurements of particle level (mass) inside the top hopper.

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