The document discusses the design optimization of an adsorber column header used in a helium purifier. Helium purification is needed to remove impurities introduced during liquefaction and other processes. Computational fluid dynamics (CFD) analysis was performed using ANSYS Fluent to analyze flow characteristics in header designs with inlet angles ranging from 90 to 20 degrees. Results showed flow distribution became more uniform as the inlet angle decreased. A 30 degree inlet angle was selected as it provided good flow characteristics while also considering manufacturability. Further optimizations to the header design could improve flow uniformity, such as adding guiding plates or modifying corner geometries.

1. DESIGN OPTIMIZATION OF ADSORBER
COLUMN HEADER USED IN HELIUM PURIFIER
Submitted By:
Sumeet
Raikwar

2. INTRODUCTION
 Helium is a rare and expensive gas. It gets contaminated
while various operations.
 Helium purification system becomes an integral part of
helium liquefaction system.
 The project deals with the design optimization of adsorber
column header used in helium purifier.
 Due to considerable diameter difference between adsorber
column and the connecting pipe there occurs the case of
sudden expansion and flow maldistribution.
 Flow maldistribution inside adsorber results in low
performance of adsorber unit. This affects the purity of
helium and also overestimate the adsorber mass.

3. NEED OF HELIUM PURIFIER
 Helium gets contaminated in the cycle with various
kinds of impurities in different components or by
other means.
 During liquefaction process, if this impure helium
enters the system they freeze earlier than Helium.
 This effect the operation and capacity of the system,
and also damages the moving parts.

4. PRINCIPLES OF HELIUM PURIFICATION
 The two-basic principle of impurity removal are
refrigeration purification and physical adsorption.
 Refrigeration purification method, impure gas is
cooled until impurities condense or freeze out.
 In physical adsorption method, impure gas passes
over a adsorber medium which traps the impurity.
 Physical adsorption helps in achieving high grade of
purity.
 In helium purification, a combination of both
refrigeration purification and physical adsorption.

5. COMPONENTS OF HELIUM PURIFIER SYSTEM
Schematic of Components of
Helium Purifier
Helium Purifier Component
Assembled in Unigrapics
(Courtesy: “Helium Purifier
component design and piping
layout, 2015)

6. PROCESS OF HELIUM PURIFICATION

7. DESIGN PARAMETERS OF HELIUM PURIFIER
Courtesy: RRCAT Indore

8. TYPES OF ADSORPTION
 There are basically two types adsorption:
 Chemical Adsorption:
• In chemical adsorption, valence force is involved in the
formation of the new compound.
• In chemical adsorption surface reactions like
reconstruction, dissociation, catalysis may take place.
• They are irreversible in nature.
 Physical Adsorption:
• There is an interaction between the gas molecule and solid
material and gas molecule stick to the surface of the solid in
layer by layer.
• Here van-der Waals forces are involved.
• The adsorption can be a mono-molecular layer or multi-
molecular layer.

9. ABOUT ADSORBER COLUMN
 Adsorber columns used is of vertical U-shaped made
up of stainless steel material and is completely
submerged inside the LN2 vessel.
 Five adsorber column of 2m in length of each
respectively are used and are combined in series.
 Coconut shell based activated charcoal used for the
purpose of adsorption.

10. OBJECTIVE OF THE STUDY
 To Minimise the flow maldistribution in present
design of header.
 Finding a solution to flow maldistribution by
analyzing different possible geometries for adsorber
column header.
 To perform ANSYS FLUENT analysis on the different
proposed geometries for header and observe the flow
characteristics.
 Concluding by choosing the optimal design and
illustrating future scope of current work.

11. LITERATURE REVIEW
 R. F. Barron, Cryogenic systems.
 R. S. Birajdar, H. K. Patel and D. M. K. Rodge, “Helium
Purifier component design and piping layout,”
Vishnupuri, Nanded, 2015.
 D. Sagar, A. Jain and A. R. Paul, “Computational Fluid
Dynamics Investigation of Turbulent separated flows
in axisymmetric diffusers,” International Journal of
engineering science and technology,2011.

12. SUDDEN EXPANSION
 There is considerable difference between the
connecting pipe and the inlet of the adsorber column
leads to loss due to sudden expansion.
 Although it comes under minor loss, but in our case it
can lead to error in calculation of adsorber bed size,
adsorber mass, velocity variation, mal-distribution of
flow and inefficient use of adsorber column.

13. FLOW MALDISTRIBUTION
 Flow maldistribution may be caused by factors like
geometry, mechanical design features, manufacturing
imperfections, tolerances and also by operating
conditions (like viscosity or density etc).
 It comes with drawbacks such as low performance of
the component, difficulty in achieving desired effect
etc.
 Our case is of geometry induced flow maldistribution
due to sudden change of flow area at inlet of adsorber
column header.

14. ABOUT CFD
 “CFD is the science of predicting fluid flow
characteristics, heat and mass transfer and associated
phenomenon by solving numerically the set of
governing mathematical equations”.
 There are several unique advantages of CFD:
• The decrease of lead times and costs of new designs.
• Access to study systems where controlled
experiments are hard or impossible to perform.
• Access to study the systems under uncertain
conditions and beyond their usual performance
limits.
 It consists of CFD codes, that are set of numerical
algorithms that can undertake fluid flow problems.
 All CFD codes contain three main components:
• Pre-processor, Solver and Post-processor.

15. GOVERNING EQUATION
 Fluid flow characteristics are basically governed by
conservation equations based upon the fundamental
physics laws of fluid mechanics, that are:
• Conservation of mass (i.e. continuity equation)
• Conservation of momentum (i.e. Newton’s second
law)
• Conservation of energy (i.e. first law of
thermodynamics)
 For steady flow, the continuity equation is:
 X-Momentum equation:

16.  Y-Momentum equation:
 Z-Momentum equation:
 Navier-Stokes equation: For constant viscosity and
steady flow and by neglecting gravitational effect,
equation is represented by,
 Energy equation:

17. ABOUT ANSYS FLUENT
 Fluent is a computer program for modelling fluid flow
in complicated geometries.
 The basic steps to obtain CFD simulated results are:
• Generating the model geometry and mesh-using
ANSYS modeller and mesh generator.
• Start the relevant solver for 2D or 3D modelling in
FLUENT.
• Introduce the grid into FLUENT and check the grid.
• Choose the solver formulation and basic equations to
be solved.
• Designation of material properties and boundary
conditions.
• Altering the solution control parameters.
• Initializing the flow field and run the solver.
• Examine and save the results.

18. ADSORBER COLUMN DESIGN PARAMETER
Parameters Designed value
Adsorber column material SS pipe
Length of adsorber column 2m
Diameter of the Adsorber Column 0.114m
Shape of adsorber column Vertical U-Shaped
Number of adsorber column 5

19. METHODOLOGY

20. TERMINOLOGIES
 Superficial Velocity: It is a hypothetical velocity
calculated as if the given fluid or phase is the only one
flowing or present in given cross-sectional area.
 Reynolds Number: Reynolds number is a
dimensionless number and is required in foretelling
flow patterns in the various fluid flows.

21. CALCULATION
 All the calculations are performed on the basis of
standard formulae.
 Data for adsorber column and the pipe has been
taken from the previous thesis work on design of
helium purifier component.
 Following data is taken from the work done at RRCAT
Indore,
At 77 K,
Flow rate=6.33x10-5 m3/s
Density of Helium (𝜌) = 61.453 Kg/m3
Dynamic Viscosity (μ) = 9.87x10-6 Kg-m/s
Diameter of the pipe (d) = 0.057m
Diameter of the adsorber Column (D) = 0.114 m

24. COMPUTATIONAL FLUID DYNAMICS DOMAIN
CREATION
 Geometry Creation: The model is prepared using
ANSYS Fluent Design Modular.
 For simplification purpose, as well as saving time and
as our area of interest is axis-symmetric, the current
geometry is simplified to 2D and axis-symmetric.

25.  Mesh generation: The process of discretizing
elements to solve a set of governing equations
throughout the computational region.
 Grid independence test: Grid Independence test is
performed in order to confirm that the meshing of the
component results in the more efficient output and is
of best in form for the respected geometry.
 The grid independence test is performed for three
grid size varying from coarse to finer, and suitable
mesh size is selected. The above mesh is performed
on the basis of grid test.

26. PROBLEM SETUP
 Start the setup by checking mesh, dimension and
display.
 The pressure-based approach was developed for low-
speed incompressible flows, hence pressure based
solver is chosen.
 Flow is steady and geometry is in 2D, axis-symmetric.
 Viscous model as Standard K-epsilon, and then
Enhanced wall treatment is chosen.
 Material properties is specified as per the material
chosen in previous thesis work.
 The Boundary conditions are as follows:
Velocity inlet and pressure outlet is opted as inlet and
outlet conditions.

27. SOLUTION
 The solution is obtained by following method as:
• SIMPLE solution method is chosen for solution.
• Under residual monitor, absolute convergence criteria
are set to 1x10-06
• Solution initialization is performed.
• Run the calculation by setting the number of
iteration.

28. RESULTS
 For 90o inlet angle of adsorber column the velocity profile is
as follows:
At Inlet Inside adsorber column

29.  For 60o inlet angle of adsorber column the velocity profile is
as follows:
At inlet Inside adsorber column

30.  For 45o inlet angle of adsorber column the velocity
profile is as follows:
At inlet Inside adsorber column

31.  For 30o inlet angle of adsorber column the velocity profile is
as follows:
At inlet Inside adsorber column

32.  For 20o inlet angle of adsorber column the velocity profile is
as follows:
At inlet Inside adsorber column

33. SKIN FRICTION COEFFICIENT GRAPHS FOR EACH GEOMETRY
 For 90o Inlet
 For 60o Inlet

34.  For 45o Inlet
 For 30o Inlet

35.  For 20o Inlet

36. OBSERVATION TABLE

37. VALIDATION
 The published data taken from research paper in International
Journal of Engineering, Science and Technology (IJEST).
 D. Sagar, A. Jain and A. R. Paul, “Computational Fluid Dynamics
Investigation of Turbulent separated flows in axisymmetric
diffusers,” International Journal of engineering science and
technology, 2011.

38. CONCLUSION
 Results show that the flow distribution becomes
more and more uniform as the angle is decreased
from 90o to 20o.
 Although the flow distribution in 20o is much uniform
but we have chosen 30o as adsorber column inlet
angle, because the variation of recirculation
length is negligible from 30o to 20o.
 30o inlet angle is chosen as final inlet angle for
adsorber column by considering all the factors like
manufacturing and fabrication aspects, fluid flow
characteristics, and space availability.

39. FUTURE SCOPE
 As every work does not have any end and there is a
chance of betterment in every field.
 Flow mal-distribution can also be reduced by turning
corners to smooth turn instead of gradual angles.
 Header column flow mal distribution can also be
reduced by introducing guiding plates.
 New adsorber column design can also be proposed
for required grade of helium purity.
 With the help of current data further header design
improvement can be performed

40. Thank you