Difference between revisions of "Design and Analysis of Modified Tesla Valve Geometry Implementation in a Filter Chamber"

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(Methodology)
(Methodology)
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The simulation model set for this research are transient, incompressible flow, subsonic flow, Large Eddy Simulation (LES) turbulence, and multiphase Eulerian - Lagrangian model. The governing equation for this model are lised as below.
 
The simulation model set for this research are transient, incompressible flow, subsonic flow, Large Eddy Simulation (LES) turbulence, and multiphase Eulerian - Lagrangian model. The governing equation for this model are lised as below.
 +
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incompressible navier stokes equation for LES turbulence model
  
  
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'''5. Fluid Properties and Boundary Conditions'''
 
'''5. Fluid Properties and Boundary Conditions'''
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The properties for the fluid and solid phase are listed as below
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{| class="wikitable"
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!colspan="5"|'''Properties'''
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|-
 +
|
 +
|Density (kg/m3)
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|Dynamic Viscosity (Pa.s)
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|Velocity Inlet (m/s)
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|Total mass (kg)
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|-
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|Flue Ash
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|1250
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| -
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|0,5
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|8
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|-
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|Flue Gas
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|0.9
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|2.14e-5
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|2
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| -
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|}
  
 
== Results and Discussion ==
 
== Results and Discussion ==

Revision as of 07:32, 6 January 2021

Introduction

Power plants all around the world use various types of fuel such as fossil fuel, coal, and natural gas to generate heat for the system to work. Combustion in coal-based power plants in particular produces large amounts of particulate matter called as fly ash which can be hazardous towards the environment and human health. For this reason, filters are used in the system to remove said particulates from the gas before it is introduced to the environment.

There are various types air controlling technologies which are implemented in power plants to improve the quality of gas released from the process. Common ones in the field are inertial seperators, fabric filters, scrubbers, and precipitators with each their own process, advantages and disadvantages.

Inertial seperators in particular are devices that are used to filter particulates from the flow of gas going through the system by changing the direction of motion of the flow (Clift, 1997). The flow direction of motion is changed through use of various geometric designs such as baffles, cavities, cross section area changes, and so on. Through sudden introduction of these geometric designs, forces in the gas will concentrate the flow of particles to specific part of the gas flow which can be then seperated in chambers or other filtering surfaces. Once seperated, the particulates from the flow are moved to an outlet hopper or containter to be stored before disposed safely. Therefore, intricate design of these geometric structures inside the seperators play important role in increasing the overall efficiency of the filtering system. As most of this system doesnt require moving parts, they are at very low cost and maintenance as well.


Comparing other systems with intricate designs, the tesla valve is a fixed-geometry check valve which allows for one direction flow of fluid going through without use of any moving parts. As it allows unobstructed flow from one direction, various geometric structures inside the valve blocks the flow greatly by rearranging the flow to block one another hence resulting in great resistance. Other than its use as a check valve, the tesla valve has been implemented as well as micromixer to increase mixing performance by taking advantage of its geometry. In this case, it poses a question in whether there are other implementations for this geometry as it has similar concept to inertial seperators in rearranging fluid flow with its internal structures.

Download (1).png

This research proposes the innovative idea of using a modified geometry of tesla valve in a particulate filtering system. The modified geometry is designed and simulated in aiming to find the feasibility of implementing similar tesla valve geometries and show how the efficiency in filtering can be affected in these systems.

Objective

For this research, the objectives are as following

  • Design a geometry based on the tesla valve for gas-solid flow seperation purposes
  • Simulate said geometric design through transient, subsonic, Incompressible, and LES configuration CFD simulation to mimic real life conditions
  • Analyze the feasibility of tesla valve based geometry in filtering through parameters including (1) efficiency in filtering, (2) range of particle sizes effective to be filtered, (3) flow patterns, and (4) number of segments
  • Verifying the result based on a grid independece study to ensure a small margin of error
  • Validate results through various other similar studies

Methodology

1. Outline of Process

The outline of this research are as the following.


Tesla Valve Diagram.png



2. Software Used

There are mainly 2 softwares used in this research which is to create the tesla valve geometry and to simulate the geometry in a CFD environment.

a. Geometry Modelling

For the geometry creation, the used software is Autodesk Inventor. Autodesk Inventor is a computer-aided design (CAD) software which provides professional-grade 3D mechanical design modelling with user friendly interfaces developed by Autodesk. Other than mechanical designing, inventor is also capable of structual simulation and documentation (drawing, animation, etc.).


b. CFD Simulation

The software used in the numerical CFD simulation especially pre-processing and solver is CFDSOF. CFDSOF is the first indonesian CFD software developed by PT CCIT Group Indonesia with a straightforward and easy to understand GUI. Geometry created from Inventor will be imported to CFDSOF to be meshed and processed numerically. Once done, the results are then analyzed with Paraview to observe various data such as flow field velocity, pressure, particulate distribution and etc.



3. Tesla Valve Geometry

Below is the geometry designed for this research with Autodesk Inventor as the CAD software. The tesla valve geometry is slightly modified from the usual form to accomodate the purpose in filtering particulates from the flow of gas. The gas still mixed with fly ash would enter the geometry from the inlet which would be then flow through the structure trying to filter particulate before exiting through the outlet. The overall dimension of this geometry is set to be 90 cm x 32 cm x 46.3 cm

Teslavalve31.png Teslavalve31iso.png


4. CFD Simulation Model

The simulation model set for this research are transient, incompressible flow, subsonic flow, Large Eddy Simulation (LES) turbulence, and multiphase Eulerian - Lagrangian model. The governing equation for this model are lised as below.

incompressible navier stokes equation for LES turbulence model



5. Fluid Properties and Boundary Conditions

The properties for the fluid and solid phase are listed as below

Properties
Density (kg/m3) Dynamic Viscosity (Pa.s) Velocity Inlet (m/s) Total mass (kg)
Flue Ash 1250 - 0,5 8
Flue Gas 0.9 2.14e-5 2 -

Results and Discussion

Conclusion

References

Clift, R. (1997). Inertial separators: basic principles. In Gas Cleaning in Demanding Applications (pp. 41-52). Springer, Dordrecht.