FIELD OF THE INVENTION
The present invention relates to an improved BLADE PROFILE FOR axial reaction
fan with enhanced aerodynamic performance.
BACKGROUND OF THE INVENTION
Fans are very essential auxiliaries to boiler for steam generation in the field of
power and process industries. These fans act in one aspect as forced draft fan
for providing air for combustion that is to say, a primary air fan for carrying
pulverized coal to combustion chamber, and in a second aspect act as induced
draft fan for exhausting the flue gases to chimney as per the system
requirement. Although, the application requirements could be catered by radial
and axial flow fan but such fans additional require control mechanism to control
the flow as per system demand at different boiler load.
The conventional Axial reaction fan (figure 1) has a Rotor Assembly [1]
consisting of Blade (2) at least one a Blade Bearing Assembly (3), an Impeller
Hub assembly (4), a Shaft (5), a Main Bearing assembly (6). The Profiled Blade
(2) is placed on the Impeller Hub assembly (4) with the Blade shaft (5) and the
Blade bearing assembly (3) which generates the required aerodynamic
parameters for example, Flow, Pressure. A suction chamber [7] uniformly guides
the flow inside the fan blade (2) through a bell mouth inlet cone [8]. The
impeller is driven by a conventional motor. The electrical energy input is
converted into the aerodynamic output by the rotating impeller. The impeller is
followed by the outlet guide (OGV) vane and a diffuser (9) which recovers the
kinetic energy of the fluid leaving the impeller.

The present inventors with experimentations and studies observed that Axial
reaction Fan for secondary air handling applications in utility and industries with
higher aerodynamic performance, must possess fan blades with at least following
blade profile criteria :-

It is pertinent to mention here that the conventional fan blades have not been
found energy efficient to meet the aerodynamic parameters for example, Flow w
coefficient φ =0.3125, Pressure Coefficient ψ = 0.4936.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to propose an improved BLADE
PROFILE FOR Axial reaction Fan with enhanced aerodynamic performance.
Another object of the invention is to propose an improved BLADE PROFILE FOR
Axial reaction Fan with enhanced aerodynamic performance, which is applicable
as secondary air handling in utility and industries.
Still another object of the invention is to propose an improved BLADE PROFILE
FOR Axial reaction Fan with enhanced aerodynamic performance, which
enhances the fan performance and reduce power consumption at different loads
of operation.

Further object of the invention is to propose an improved BLADE PROFILE FOR
Axial reaction Fan with enhanced aerodynamic performance, which exhibits
better pressure and volume performance.
The foregoing has outlined some of the pertinent objective of the invention.
These objective should not be construed to be merely illustrative of some of the
more prominent features and applications of the intended invention. Many other
beneficial results can be obtained by applying the disclosed invention in a
different manner or modifying the invention within the scope of disclosure.
Accordingly, other objectives and a full understanding of the invention and the
detailed description of the preferred embodiment in addition to the scope of
invention are described as under:
These and other objects and advantages of the invention will be apparent from
the ensuing description.
SUMMARY OF THE INVENTION
Accordingly, there is provided an improved Axial reaction Fan with enhanced
aerodynamic performance.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from the
ensuing description when read in conjunction with the accompanying drawings
wherein :

Figure 1 : Schematic illustration of Conventional Axial Profiled Fan
Figure 2 : Shows a fan blade with innovative blade profile adapted in
the axial reaction fan according to the invention.
Figure 3 : Shows a modified outlet vane guide (OGV) adapted in the
improved fan of the invention.
While the invention is described in conjunction with the illustrated embodiment,
it is to be understood that such illustration is not intended to limit the invention
to the disclosed preferred embodiment. On the contrary, it is intended to cover
all alternatives, modifications and equivalents as may be included within the
spirit and scope of the invention disclosure.
DETAILED DESCRIPTION OF THE INVENTION
At the outset of the description, which follows, it is to be understood that the
ensuing description only illustrates a particular form of this invention. However,
such a particular form is only an exemplary embodiment, and without intending
to imply any limitation on the scope of this invention. Accordingly, the description
is to be understood as an exemplary embodiment and teaching of the invention
and not intended to be taken restrictively.
For the purpose of promoting an understanding of the principles of the invention,
reference is now made to the embodiment illustrated in the drawings and
specific language is used .to describe the same. It is nevertheless to be
understood that no limitations of the scope of invention is hereby intended, such

alterations and further modifications in the illustrated embodiment and such
further applications of the principals of the invention as illustrated therein being
contemplated as would normally occur to one skilled in the art to which the
invention relates.
The current invention illustrates an improved. Axial reaction fan having a fan
blade with innovative profile, the blade of the fan is cambered, and Staggered
with a profile including smoothly entry and exit angles for flow separation and
pressure development for high pressure application. Dimensions of the Profile
cross section and staggering of different cross sections have been optimized to
extract maximum kinetic energy. The improvement also includes a modified OGV
of radius of curvature corresponding to the new blade for smooth stream lining
of flow to the diffuser.
As shown in figure 2, the improved axial reaction fan is provided with a fan blade
having blade profile for enhancing aerodynamic performance having flow
coefficient φ = 0.3125 and Pressure Coefficient φψ= 0.4936. An outlet guide vane
(OGV (10) is disposed next to the impeller for guiding the flow smoothly which
recovers the kinetic energy of the fluid leaving the impeller. The axial reaction
fan of the invention consists of a Rotor Assembly [1] provided with a profiled
blade (2), a Blade Bearing Assembly (3), an Impeller Hub assembly (4), a Shaft
(5), and a Main Bearing assembly (6). The Profiled Blade (2), placed on the
Impeller Hub assembly (4) with the Blade shaft (5) and Blade bearing assembly
(3) which generates the required aerodynamic parameters for example, Flow,
and Pressure. A suction chamber [7] is provided to uniformly guide the flow
inside the fan blade through a bell mouth inlet cone [8]. The impeller is driven by

a conventional motor. The electrical energy input is converted into aerodynamic
output by the rotating impeller.
A 1800 mm Prototype Blade Profile has been designed, manufactured and
performance tested. Results shown that there is a considerable improvement on
aerodynamic. Efficiency (about 4% comparing with conventional design). The
developed Blade profile for Axial Profiled Fan (figure 2) is having a distinct
camber of profile with novel leading and trailing edge design with different
profiled cross sections in meridonial cross section.

WE CLAIM :
1. An improved Axial reaction Fan with enhanced aerodynamic performance,
comprising :
- a rotor assembly having an impeller hub accommodating at least one fan
blade disposed on a shaft arranged over a blade bearing means;
- a main bearing assembly supporting the rotor assembly; and
- an outlet guide vane disposed adjacent to the impeller to guide fluid flow
and recover the kintetic energy of the fluid leaving the impeller;
the improvement is characterized in that the at least one fan blade is
profiled to produce aerodynamic parameters of flow co-efficient (φ) and
pressure coefficient ψ of 0.3125 and 0.4936 respectively with 87%
efficiency (η), and in that the outlet guide vane is configured, with a
radius of curvature enabled to stream line the flow to improve efficiency
of the fan.
2. The fan as claimed in claim 1, comprising a suction chamber to uniformly
guide the flow inside the fan blade through a bell mouth inlet cone.

3. The fan as claimed in claim 1, wherein the impeller is operated through an
electrical motor.

ABSTRACT

The invention relates to an improved BLADE PROFILE FOR Axial reaction
Fan with enhanced aerodynamic performance, comprising : a rotor
assembly having an impeller hub accommodating at least one fan blade
disposed on a shaft arranged over a blade bearing means; a main bearing
assembly supporting the rotor assembly; and an outlet guide vane
disposed adjacent to the impeller to guide fluid flow and recover the
kinetic energy of the fluid leaving the impeller; the improvement is
characterized in that the at least one fan blade is profiled to produce
aerodynamic parameters of flow co-efficient (φ) and pressure coefficient
ψ of 0.3125 and 0.4936 respectively with 87% efficiency (η), and in that
the outlet guide vane is configured, with a radius of curvature enabled to
stream line the flow to improve efficiency of the fan.