Fan with heat dissipating outlet guide vanes

Abstract

A method for designing a fan having a motor which drives an impeller comprises providing an outlet guide vane assembly which includes a hub and a plurality of guide vanes that extend radially outwardly from the hub, attaching the hub to the motor, determining an approximate amount of heat which is generated by the motor during operation of the fan, determining an approximate surface area which is required to dissipate the heat into a surrounding air stream, and configuring the guide vanes to comprise a total surface area which is approximately equal to the required surface area. In this manner, the heat generated by the motor during operation of the fan can be dissipated by the guide vanes.

1 . A method for designing a fan which includes a motor that drives an impeller, the method comprising:
 providing an outlet guide vane assembly which includes a hub and a plurality of guide vanes which extend radially outwardly from the hub;   attaching the hub to the motor;   determining an approximate amount of heat which is generated by the motor during operation of the fan;   determining an approximate surface area which is required to dissipate a substantial amount of the heat into a surrounding air stream; and   configuring the guide vanes to comprise a total surface area which is approximately equal to the required surface area;   wherein the heat generated by the motor during operation of the fan can be dissipated by the guide vanes into the surrounding air stream.   
   
   
       2 . The method of  claim 1 , wherein the step of determining the required surface area comprises determining a film coefficient for the guide vanes. 
   
   
       3 . The method of  claim 1 , wherein the step of configuring the guide vanes comprises:
 designating a plurality a radially spaced airfoil segments for each guide vane, each of which comprises a chord, an area and a perimeter length;   determining the chord, area and perimeter length of each airfoil segment which will result in the guide vanes comprising a total surface area which is approximately equal to the surface area required to dissipate the heat.   
   
   
       4 . The method of  claim 3 , further comprising adjusting the chord, area and perimeter length of each airfoil segment to decrease the effective thermal resistance of the heat transfer path through the guide vanes. 
   
   
       5 . The method of  claim 3 , further comprising adjusting the chord, area and perimeter length of each airfoil segment to decrease the effective thermal resistance of the heat transfer path between the guide vanes and a surrounding air stream. 
   
   
       6 . The method of  claim 3 , wherein the plurality of airfoil segments comprises a first airfoil segment which is located closest to the hub, an n th  airfoil segment which is located farthest from the hub and a number of additional airfoil segments which are located between the first and the n th  airfoil segments, and wherein the method further comprises making at least one of the chord, the area and the perimeter length of the first airfoil segment greater than the chord, the area or the perimeter length of the n th  airfoil. 
   
   
       7 . The method of  claim 6 , further comprising making the chord, the area and the perimeter length of the first airfoil segment greater than the chord, the area and the perimeter length of the n th  airfoil segment. 
   
   
       8 . The method of  claim 6 , further comprising making at least one of the chord, the area and the perimeter length of the first airfoil segment greater than the chord, the area or the perimeter length of the remaining airfoil segments. 
   
   
       9 . The method of  claim 6 , further comprising making the chord, the area and the perimeter length of the first airfoil segment greater than the chord, the area and the perimeter length of the remaining airfoil segments. 
   
   
       10 . The method of  claim 1 , wherein the step of attaching the hub to the motor comprises:
 providing a housing for the motor; and   forming the hub integrally with the housing.   
   
   
       11 . The method of  claim 10 , further comprising forming the motor housing and the outlet guide vane assembly as an integral unit from a single piece of a heat conducting material. 
   
   
       12 . A fan which comprises:
 an outlet guide vane assembly which includes a hub and a plurality of guide vanes which extend radially outwardly from the hub; and   a motor which includes a housing that is connected to or formed integrally with the hub and which during operation of the fan generates heat;   wherein the guide vanes together comprise a total surface area which is approximately equal to a surface area which is required to dissipate a substantial amount of the heat into a surrounding air stream.   
   
   
       13 . The fan of  claim 12 , wherein each of the guide vanes comprises a plurality a radially spaced airfoil segments, each of which includes a chord, an area and a perimeter length. 
   
   
       14 . The fan of  claim 13 , wherein the plurality airfoil segments comprises a first airfoil segment which is located closest to the hub, an n th  airfoil segment which is located farthest from the hub and a number of additional airfoil segments which are located between the first and the n th  airfoil segments. 
   
   
       15 . The fan of  claim 14 , wherein at least one of the chord, the area and the perimeter length of the first airfoil segment is greater than the chord, the area or the perimeter length of the n th  airfoil segment. 
   
   
       16 . The fan of  claim 14 , wherein the chord, the area and the perimeter length of the first airfoil segment are greater than the chord, the area and the perimeter length of the n th  airfoil segment. 
   
   
       17 . The fan of  claim 14 , wherein at least one of the chord, the area and the perimeter length of the first airfoil segment is greater than the chord, the area or the perimeter length of the remaining airfoil segments. 
   
   
       18 . The fan of  claim 14 , wherein the chord, the area and the perimeter length of the first airfoil segment is greater than the chord, the area and the perimeter length of the remaining airfoil segments. 
   
   
       19 . The fan of  claim 14 , wherein the distance between successive segments is generally constant. 
   
   
       20 . The fan of  claim 19 , wherein relationship between at least one of the chords, the areas and the perimeter lengths of the airfoil segments is non-linear. 
   
   
       21 . The fan of  claim 19 , wherein the relationships between the chords, the areas and the perimeter lengths of the airfoils segments are non-linear. 
   
   
       22 . The fan of  claim 12 , wherein the motor comprises a stator which forms an interference fit with the housing. 
   
   
       23 . The fan of  claim 12 , further comprising a number of radially extending cooling fins which are attached to or formed integrally with the motor housing. 
   
   
       24 . A fan which comprises:
 an outlet guide vane assembly which includes a hub and a plurality of guide vanes which extend radially outwardly from the hub; and   a motor which includes a housing that is connected to or formed integrally with the hub and which during operation of the fan generates heat;   wherein each of the guide vanes comprises a plurality a radially spaced airfoil segments, each of which includes a chord, an area and a perimeter length.   wherein the plurality airfoil segments comprises a first airfoil segment which is located closest to the hub, an n th  airfoil segment which is located farthest from the hub and a number of additional airfoil segments which are located between the first and the n th  airfoil segments.   wherein at least one of the chord, the area and the perimeter length of the first airfoil segment is greater than the chord, the area or the perimeter length of the n th  airfoil segment.   
   
   
       25 . The fan of  claim 24 , wherein the chord, the area and the perimeter length of the first airfoil segment are greater than the chord, the area and the perimeter length of the n th  airfoil segment. 
   
   
       26 . The fan of  claim 24 , wherein at least one of the chord, the area and the perimeter length of the first airfoil segment is greater than the chord, the area or the perimeter length of the remaining airfoil segments. 
   
   
       27 . The fan of  claim 24 , wherein the chord, the area and the perimeter length of the first airfoil segment is greater than the chord, the area and the perimeter length of the remaining airfoil segments. 
   
   
       28 . The fan of  claim 24 , wherein the distance between successive segments is generally constant. 
   
   
       29 . The fan of  claim 28 , wherein relationship between at least one of the chords, the areas and the perimeter lengths of the airfoil segments is non-linear. 
   
   
       30 . The fan of  claim 19 , wherein the relationships between the chords, the areas and the perimeter lengths of the airfoils segments are non-linear.