Heat Shield Rail Orifice Machining for Diffuser Cooling Flow
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Solution Overview
Problem
The existing methods for forming orifices in rail members of heat shield panels in gas turbine engines are inefficient, particularly in creating diffuser-shaped impingement orifices that effectively manage cooling flows and thermal protection within the combustor section.
Innovation Solution
A method involving a hole boring tool positioned at specific angles to create first and second cuts through the rail member, resulting in diffuser-shaped orifices with increasing cross-sectional areas from the inner to the outer wall, enhancing cooling efficiency by directing cooling flows effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional drilling methods are used to form orifices in rail members, then the manufacturing process is simple, but the cooling flow pressure and coverage are insufficient
Solution Approach 1:
The orifice formation process is divided into multiple sequential cutting passes instead of a single drilling operation. The hole boring tool makes a first cut at a first angle, then a second cut at a second angle, creating a diffuser-shaped orifice through segmented material removal. This segmentation enables better cooling flow control while maintaining manufacturing feasibility through standardized multi-pass machining operations.
Solution Approach 2:
The invention transitions from conventional single-angle drilling to multi-angle sequential cutting, adding angular dimensionality to the orifice formation process. By varying the tool angle between cuts and creating a diffuser shape with increasing cross-sectional area, the process achieves superior cooling flow characteristics that cannot be obtained through traditional axial drilling alone.
2Productivity
If diffuser-shaped orifices are formed through multi-angle cutting, then cooling flow pressure and coverage increase, but manufacturing time increases
Solution Approach 1:
The hole boring tool performs cutting operations continuously in sequence without removing the workpiece from the fixture. The tool transitions from making the first cut at the first angle to making the second cut at the second angle in a continuous manufacturing cycle, eliminating setup and repositioning time. This continuous action maintains high cooling efficiency while minimizing manufacturing cycle time extension.
3Reliability
If the orifice cross-sectional area increases from inner wall to outer wall, then thermal protection improves, but manufacturing precision requirements increase
Solution Approach 1:
The invention systematically varies the tool angle and cutting depth parameters between the first and second cuts to create the desired diffuser shape. By controlling the angle of the hole boring tool and the extent of material removal in each pass, the process achieves the specified cross-sectional area gradient while maintaining manufacturability through controlled parameter changes rather than requiring ultra-precise single-pass machining.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A method of forming an orifice (320) through a rail member (308) of a heat shield panel (300) having a cold side surface (304) is provided. The method comprises: positioning the rail member (308) at a first position relative to a hole boring tool (309), where the hole boring tool (309) is at a first predetermined angle relative to the cold side surface (304); forming a first cut (313) into the rail member (308) using the hole boring tool (309), the first cut (313) extending partially through the rail member (308); positioning the rail member (308) at a second position relative to the hole boring tool (309), where the hole boring tool (309) is at a second predetermined angle relative to the cold side surface (304); forming a second cut (317) into the rail member (308) using the hole boring tool (309), the second cut (317) extending completely through the rail member (308) and intersecting a portion of the first cut (313) to form the orifice (320), extending through the rail member (308), from an inner wall (312) of the rail member (308) to an outer wall (310) of the rail member (308), the orifice (320) having a cross sectional area that increases from the inner wall (312) to the outer wall (310).