Perforated Flame Holder in Water Heaters for Stable Combustion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional water heaters face inefficiencies in heat transfer and combustion control, particularly in maintaining consistent water temperature and reducing pollutant production during frequent start-ups, due to limitations in flame holder positioning and preheating methods.
Innovation Solution
A water heater system incorporating a perforated flame holder with a plurality of apertures, positioned within the flue to hold a flame and transfer heat efficiently, and a controller that regulates fuel flow based on temperature sensors to optimize combustion and heat distribution, along with an optional electrical heating element for preheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional flame holder is used, then the structure is simple, but heat transfer efficiency is poor and water temperature consistency deteriorates
Solution Approach 1:
The flame holder is designed with multiple apertures that segment the flame into multiple smaller combustion zones. This segmentation increases the surface area for heat transfer and improves water temperature consistency while maintaining manufacturing simplicity through standardized aperture patterns.
Solution Approach 2:
The flame holder incorporates a porous structure with multiple apertures that allow fuel and air to pass through and support distributed combustion. This porous design significantly enhances heat transfer efficiency compared to solid conventional flame holders while remaining manufacturable using standard drilling or machining processes.
2Adaptability or versatility
If frequent start-ups occur, then operational flexibility is improved, but pollutant production increases
Solution Approach 1:
The system includes a preheating mechanism that prepares the flame holder and combustion chamber before main combustion begins. This preliminary action ensures stable ignition during frequent start-ups and reduces incomplete combustion pollutants by establishing proper combustion conditions before fuel is fully introduced.
Solution Approach 2:
The control system monitors combustion parameters and provides feedback to adjust fuel flow and air supply during start-up and operation. This feedback control optimizes combustion efficiency during frequent start-ups, reducing pollutant emissions while maintaining operational flexibility.
3Ease of operation
If flame holder positioning is not optimized, then installation is easier, but water temperature consistency deteriorates
Solution Approach 1:
The flame holder is designed with a universal mounting structure that can be installed at multiple positions within the combustion chamber while maintaining effective performance. The multi-aperture design provides functional redundancy that compensates for positioning variations, ensuring water temperature consistency regardless of exact installation location.
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 system achieves improved heat transfer efficiency, reduced pollutant production, and faster recovery times by maintaining the flame within the apertures and using intelligent control to manage fuel flow, enhancing overall operational efficiency and water heating performance.
Implementation Method 1
A fuel stream is emitted from a nozzle into the flue and mixed with combustion air. The mixed fuel and combustion air undergo combustion within a perforated flame holder.
Implementation Method 2
Heat liberated from the combustion raises the temperature of the flame holder, which can glow incandescently when in operation. Infrared radiation from the flame holder and convective heat transfer from heated combustion products heats the wall of the flue and the flue convectively heats the fluid.
Implementation Method 3
Infrared radiation from the flame holder and convective heat transfer from heated combustion products heats the wall of the flue
Data Source
AI summary
A water heater includes a water tank having an inlet and an outlet, and a flue extending through the tank. A nozzle is positioned near a first end of the flue, arranged so as to emit a fuel stream into the flue, and a flame holder is located within the flue in a position to receive the fuel stream and to hold a flame entirely within the flue.