Offset Inlet Mixer for Immiscible Fluids
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Solution Overview
Problem
Existing mixers for gas turbine engines fail to achieve uniform distribution of immiscible fluids like fuel and water due to their immiscible nature, leading to inefficient combustion and increased NOX emissions, and are often complex and costly to maintain.
Innovation Solution
A mixer design with a housing featuring a flow passage and offset fluid inlets that induce swirl and include flow constrictions to enhance turbulent mixing, utilizing a swirler and offset axes to ensure uniform mixing of immiscible fluids before injection into the combustor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If water and fuel are mingled together in fuel lines prior to injection, then a single set of injectors can be used, but the two immiscible fluids arrive at the injectors in a highly unmixed state
Solution Approach 1:
The mixer performs preliminary mixing of water and fuel in a dedicated mixing chamber before the fluids reach the injector. The offset second inlet introduces water downstream of the first inlet, creating preliminary turbulence and mixing action before injection, ensuring uniform distribution at the injector face.
Solution Approach 2:
The second fluid inlet is offset from the main longitudinal axis of the flow passage, creating an asymmetric flow pattern. This offset inlet introduces fluid along a path that is offset with respect to the main axis, inducing swirl and enhancing mixing of the immiscible fluids before they reach the injector.
2Stability of the object's composition
If separate fuel and water injectors are provided, then uniform spray patterns of both fluids can be achieved, but the complexity and cost of the engine increases
Solution Approach 1:
The patent merges the fuel and water injection functions into a single injector assembly. The mixer housing combines both fluid streams and delivers them through a common outlet to a single injector, eliminating the need for separate fuel and water injection systems while maintaining uniform spray patterns.
Solution Approach 2:
The mixer housing acts as an intermediary device between separate water and fuel sources and the single injector. It provides a dedicated mixing chamber with offset inlets that pre-mix the immiscible fluids before they enter the injector, enabling a single injector to handle both fluid streams uniformly.
3Object-generated harmful factors
If water is injected into the combustor with fuel, then combustion temperature is lowered and NOX emissions are reduced, but uniform distribution of water and fuel within the combustor is difficult to achieve
Solution Approach 1:
The mixer performs preliminary mixing of water and fuel in a dedicated chamber before injection into the combustor. The offset second inlet creates turbulence and swirl that ensures uniform distribution of both fluids is achieved before they enter the combustor, preventing segregation during injection.
Solution Approach 2:
The asymmetric offset inlet configuration induces swirl flow patterns that enhance mixing and ensure uniform distribution of water and fuel in the combustor. This swirl action prevents the immiscible fluids from separating during injection and combustion.
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
The mixer achieves a substantially uniform mixture of immiscible fluids, reducing NOX emissions and simplifying the engine design by ensuring effective fuel-water mixing, demonstrated through computational fluid dynamics analysis with fuel volume fractions around 32-39% at the outlet.
Implementation Method 1
The second fluid inlet defines a secondary axis that is offset with respect to the main longitudinal axis of the flow passage to introduce fluid along a path that is offset with respect to the main longitudinal axis for inducing swirl on fluids introduced at the first and second fluid inlets
Implementation Method 2
a mixer section having a flow constriction defined in a downstream portion of the flow passage with a flow area smaller than that of the upstream portion of the flow passage for enhancing turbulent mixing of fluids introduced at the first and second fluid inlets
Data Source
AI summary
A mixer for mixing immiscible fluids includes a mixer housing defining a flow passage therethrough from a first fluid inlet to an outlet thereof. An upstream portion of the flow passage defines a main longitudinal axis. A second fluid inlet is provided downstream of the first fluid inlet in fluid communication with the upstream portion of the flow passage. The second fluid inlet is offset with respect to the main longitudinal axis of the flow passage to introduce fluid along a path that is offset with respect to the main longitudinal axis for inducing swirl on fluids introduced at the first and second fluid inlets. In certain embodiments, a mixer section is included having a flow constriction defined in a downstream portion of the flow passage with a flow area smaller than that of the upstream portion of the flow passage for enhancing turbulent mixing of fluids therein.