Optical window system with aero-optical conductive blades

Abstract

A method of improving optical characteristics of an optical window operating in a flow of fluid and having first and second panes of optically transmissive material—each having an edge adjacent to, parallel with, and at least partially coextensive with each other—is described herein. The method includes inserting a thermally conductive blade between two adjacent edges of the first and second panes of optically transmissive material; and lifting an adverse flow stagnation zone forward of the optical window by protruding the thermally conductive blade into the flow of fluid from an outer surface of the panes of the optical window.

1 . An optical window for use in a fluid flow, the window comprising:
 a first pane of optically transmissive material;   a second pane of optically transmissive material having an edge adjacent to, parallel with, and at least partially coextensive with a corresponding edge of the first pane; and   a blade made of thermally conductive material positioned between the adjacent edges of the first and second panes;   wherein the blade extends beyond a surface of the panes into the flow.   
     
     
         2 . The optical window of  claim 1 ,
 wherein the panes are angled with respect to each other forming a convex side exposed to the flow, and   wherein the blade extends from the convex side of the panes.   
     
     
         3 . The optical window of  claim 1 , wherein the blade has a head that extends along the adjacent edges defining a height of the blade, and a body extending from the head toward the pane edges defining a depth of the blade. 
     
     
         4 . The optical window of  claim 3 , wherein the head is spaced from the surface of the panes protruding into the flow and the body extends between the adjacent edges of the panes. 
     
     
         5 . The optical window of  claim 3 , wherein the body of the blade is thinner than the head in a direction perpendicular to the depth and the height. 
     
     
         6 . The optical window of  claim 1 , wherein at least a portion of the blade is moveable with respect to the panes and spacing between a leading edge of the blade and the panes is controllable. 
     
     
         7 . The optical window of  claim 1 , further comprising a heating element thermally associated with the blade and controllable to heat the blade. 
     
     
         8 . The optical window of  claim 1 , further comprising:
 a third pane having an edge adjacent to, parallel with, and at least partially coextensive with a second edge of the first pane; and   a second blade made of thermally conductive material positioned between the adjacent edges of the first and third panes;   wherein the second blade extends beyond the surface of the panes into the flow.   
     
     
         9 . The optical window of  claim 8 , wherein the cross-section of the first blade taken in a plane perpendicular to the adjacent edges of the first and second panes is the same as the cross-section of the second blade. 
     
     
         10 . The optical window of  claim 9 , wherein the cross-section of the first blade taken in a plane perpendicular to the adjacent edges of the first and second panes is different than the cross-section of the second blade. 
     
     
         11 . The optical window of  claim 1 , further comprising a thermally conductive frame in which the panes are disposed and adhesively bonded to. 
     
     
         12 . The optical window of  claim 11 , wherein the blade is thermally coupled to the conductive frame. 
     
     
         13 . The optical window of  claim 1 , wherein the panes are flat. 
     
     
         14 . The optical window of  claim 1 , wherein the blade has an arrow-shaped cross-section taken in a plane perpendicular to the adjacent edges. 
     
     
         15 . A method of improving optical characteristics of an optical window operating in a flow of fluid and having first and second panes of optically transmissive material each having an edge adjacent to, parallel with, and at least partially coextensive with each other, the method comprising:
 inserting a thermally conductive blade between two adjacent edges of the first and second panes of optically transmissive material; and   lifting an adverse flow stagnation zone forward of the optical window by protruding the thermally conductive blade into the flow of fluid from an outer surface of the panes of the optical window.   
     
     
         16 . The method of  claim 15 , wherein the step of lifting includes spacing a head of the blade from the surface of the panes. 
     
     
         17 . The method of  claim 15 , further comprising moving at least a portion of the blade with respect to the panes to control spacing between a leading edge of the blade and the panes. 
     
     
         18 . The method of  claim 15 , further comprising heating a heating element thermally associated with the blade to heat the blade. 
     
     
         19 . The method of  claim 15 , further comprising disposing the panes in and adhesively bonding the panes to a thermally conductive frame. 
     
     
         20 . The method of  claim 15 , further comprising thermally coupling the blade to a conductive frame.