Combustor Fuel Nozzle Wetting Surface for Low-Airflow Atomization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aircraft engine combustors face reduced atomization performance of liquid fuel when the flow velocity of combustion air is slow, leading to the formation of large liquid droplets due to the formation of liquid reservoirs.
Innovation Solution
The aircraft engine combustor incorporates a tubular member with a distal end surface and outlet end portion designed with contact angles less than 90 degrees, coated with lipophilic films or featuring surface unevenness to enhance atomization by increasing interface tension and promoting hydrodynamic instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the flow velocity of combustion air is high, then liquid droplets having small particle diameter are formed, but in a case where the flow velocity of combustion air is slow, liquid reservoir having greater thickness is formed resulting in large particle diameter droplets
Solution Approach 1:
The patent changes the surface energy parameter of the tubular member by coating it with a hydrophobic coating layer. This parameter change causes the liquid fuel to be repelled from the surface, preventing liquid reservoir formation even at low flow velocities and enabling consistent atomization performance across different combustion air flow conditions
Solution Approach 2:
The patent replaces the mechanical atomization mechanism (relying on high flow velocity to create hydrodynamic instability) with a surface property-based mechanism (hydrophobic surface repulsion). This substitution allows atomization to occur effectively regardless of flow velocity by using the hydrophobic property to control liquid fuel behavior
2Manufacturing precision
If hydrodynamic instability is imparted to liquid reservoir, then liquid droplets are formed, but large particle diameter droplets are formed reducing atomization performance
Solution Approach 1:
The patent extracts the liquid fuel from forming large liquid reservoirs by applying a hydrophobic coating to the tubular member surface. This removes the problematic liquid reservoir formation mechanism entirely, allowing only thin liquid films to form which then atomize efficiently without creating large droplets
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 configuration improves atomization performance by stabilizing liquid fuel on the surface, lengthening liquid threads, and forming smaller droplets, even at low airflow velocities.
Implementation Method 1
the entire distal end surface in a circumferential direction extending from an outlet end of the inner peripheral surface toward an outside in a radial direction has a first contact angle smaller than 90 degrees with respect to the liquid fuel
Implementation Method 2
the lipophilic film is configured to have a contact angle of 45 degrees or less with respect to the liquid fuel, thereby the interface tension with the liquid fuel is increased, and the liquid fuel jetted from the fuel nozzle is stabilized on the inner peripheral surface of the tubular member
Data Source
AI summary
An aircraft engine combustor equipped with a cylindrical member for demarcating an internal space which extends along an axis, and a fuel nozzle which is positioned in a manner such that at least a part thereof is positioned inside the internal space, and has an injection hole through which a liquid fuel is injected toward the inner-circumferential surface of the cylindrical member, wherein the cylindrical member is configured in a manner such that the entirety, in the circumferential direction, of a tip end surface extending radially outward from the discharge port end of the inner-circumferential surface has a first contact angle relative to the liquid fuel which is less than 90°.