'HPAC Webinar-Radial Fan Analysis' simulation project by Ali_Arafat


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I created a new simulation project called 'HPAC Webinar-Radial Fan Analysis':

HPAC webinar project for Blade variation study of a Radial Fan


More of my public projects can be found here.


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Description


HPAC (Heating Plumbing and Air Conditioning) magazine is taking several proactive strides to keep the reader well-informed about contemporary developments in the mechanical as well as energy industry. Its editorial is aimed at management level mechanical industry personnel who have documented training in their fields of work.
 
Known to cover a multitude of topics from Controls and Hydronics to HVAC systems and Solar, HPAC conducted a workshop together with SimScale regarding the blade variation study of a radial fan.
Radial fans (also known as centrifugal fans) have a wide range of applications ranging from being used as draft fans in power plants to drying fans in the food industry. Being one of the most prevalent fans in the industry, it is paramount for engineers to bear in mind the performance characteristics and mechanical efficiency of the device.
 
Essentially, a radial fan is a simple mechanical device that changes the velocity and direction of a fluid passing through it. In this project, we consider air as the working fluid. The air-stream enters the fan intake at the central region in a direction parallel to the axis of the fan. The blades, run by an electric motor, push the air radially outwards in a direction that is tangential to the trailing (outer) edge of the fan blade. Therefore, not only does it increase the velocity of the airstream but also renders the direction of flow as perpendicular to the original one.
 

Project Goals


 
The paramount goal of this project is to analyze the effect of blade variation in a radial fan. We intend to perform a comparative study of the following fans:
 

  1. Radial fan: 8 blades = Fan1
     
  2. Radial fan: 16 blades = Fan 2
     
    With the help of the SimScale platform, we have simulated both the radial fan models in action. To determine and compare the performance of the fans, we trace the airflow trajectories.
     

     

Geometries


 


 
The CAD model looks like any regular radial (or centrifugal) fan available in the market.
Both, the 8 blade and the 16 blade designs are imported onto the SimScale platform before initiating the processing.
 
You can gain a better idea of the geometry by having a look at the images below:
 
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Overall fan geometry
 
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Peek on the internal fan geometry
 
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Cross sectional view of Fan 1 (8 blades)
 
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Cross sectional view of Fan 2 (16 blades)
 

Meshes


 
A hex-dominant parametric (only CFD) mesh has been created using 16 computing cores along with a Cartesian box enclosing the entire mesh of the fan. This would be the region considered for our study. Multiple mesh refinements are made on the surface of the rotor and casing before running the simulation.
 
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Meshed geometry: Isometric view
 
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Mesh refinements in the vicinity of rotor
 

Simulations


 
Using the k-omega SST model, a steady state analysis is performed assuming air as an incompressible fluid. Due to the heavy geometry and multiple mesh refinements, the simulation is executed using 32 cores and takes approximately 13 hours to run.
 

Results and Conclusions


 
Shown below are the contours of pressure and velocity of the air flow through the radial fan.
 
Pressure
 


 
Velocity
 

 
Comparison plots
 

 
As can be seen from the plots above, the total pressure rise is much higher for the 16 bladed fan variant. This leads to a higher flow coefficient for the same speed of rotation.