Heater Wall Dimples for Gas Flow Control and Heat Flux Equalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing heater designs face challenges in maintaining the flow of combustion air, fuel, and products of combustion adjacent to the heater wall without relying on circular or oval configurations, which limits design flexibility and leads to disruptions in gas circulation and uneven radiant heat flux.
Innovation Solution
The use of dimples or structures on the inner surface of the heater wall creates beneficial pressure gradients, transitioning laminar flow to turbulent flow with greater momentum, preventing separation from the wall and ensuring continuous gas circulation and equalized radiant heat flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular or oval heater enclosure is used to maintain gas flow against the wall, then the boundary layer remains adhered to the wall, but the design flexibility is limited
Solution Approach 1:
The invention applies dimples at specific locations on the heater wall surface to create localized low-pressure zones. Instead of requiring the entire enclosure to be circular or oval, only specific areas have modified geometry (dimples) to generate the necessary suction force that keeps the boundary layer adhered to the wall, thus maintaining reliability while allowing overall design flexibility.
Solution Approach 2:
The invention transitions from modifying the global three-dimensional shape of the heater enclosure (circular/oval cross-section) to making localized two-dimensional modifications (dimples) on the wall surface. This dimensional shift allows the bulk of the enclosure to maintain any desired shape while still achieving boundary layer control through localized surface features.
2Productivity
If the boundary layer separates from the heater wall, then the main flow of gases is disrupted, but maintaining adhesion requires complex heater geometry
Solution Approach 1:
Rather than making the entire heater enclosure complex (circular or oval), the invention introduces localized dimples at specific positions where boundary layer separation is most likely to occur. These dimples create localized low-pressure zones that generate suction, preventing separation only where needed and maintaining simple overall heater geometry.
Solution Approach 2:
The dimples are positioned upstream of potential separation points to create low-pressure zones in advance. This preliminary action generates suction force before the boundary layer can separate, preventing disruption to the main gas flow and maintaining circulation efficiency without requiring complex heater design.
3Reliability
If dimples are added to the heater wall, then gas flow is maintained against the wall, but the heater wall structure becomes more complex
Solution Approach 1:
The invention introduces dimples only at specific critical locations on the heater wall where boundary layer separation is most likely to occur, rather than modifying the entire wall surface. This localized approach maintains gas flow stability at key positions while minimizing the overall structural complexity and number of dimples required.
Solution Approach 2:
The invention uses a limited number of dimples at strategically selected positions rather than covering the entire heater wall. This partial action is sufficient to prevent boundary layer separation and maintain reliable gas flow, avoiding the excessive complexity that would result from comprehensive wall modification.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for flexible heater enclosure designs, maintains gas circulation against the wall, reduces disruptions, and enhances radiant heat flux uniformity, leading to improved heat transfer and extended tube life by preventing fouling.
Implementation Method 1
Dimples or other structures create beneficial pressure gradients that attach the boundary layer and main flow against the heater wall
Implementation Method 2
The turbulent flow created by dimples or other structures has a higher velocity than the laminar flow and in turn greater momentum
Implementation Method 3
The boundary layer is a thin layer of gases which move along the surface of the wall in between the surface of the wall and the main flow of gases
Implementation Method 4
improve or equalize the radiant heat flux from the heater wall to a double fired coil
Data Source
AI summary
A method and apparatus for controlling the flow of combustion air, fuel and products of combustion in a heater and equalizing radiant heat flux by providing a structure on one or more of the heater walls that attaches the boundary layer and main flow to the heater wall and increases wall surface area and view angles.