Inner-Outer Tube Combustion Heater for Stable Recirculating Flame
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional combustion heaters face challenges in maintaining uniform temperature distribution and stability of the flame, leading to reduced heating efficiency and increased NOx production, while also being costly due to complex manufacturing processes involving porous tubes.
Innovation Solution
A combustion heater design featuring an inner tube with a supply passage and an outer tube with a separated combustion space, where a stagnation point is formed to facilitate a circulating flow, allowing for stable flame formation and maintenance without the need for additional flame holding mechanisms or porous tubes, thereby improving heating efficiency and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous tube is used to form a stable flame, then flame stability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention extracts the flame stabilization function from the porous tube structure and relocates it to a dedicated flame holding member positioned in the combustion chamber. This separates the flame holding function from the gas distribution function, allowing each component to be optimized independently and manufactured separately, thereby reducing overall manufacturing complexity while maintaining flame stability.
Solution Approach 2:
The invention introduces a flame holding member as an intermediary component between the porous tube and the combustion chamber. This mediator captures the unstable flame from the porous tube and stabilizes it at a controlled position, enabling stable combustion without requiring the entire porous tube structure to provide flame stability, thus simplifying manufacturing.
2Reliability
If combustion is terminated midway in the radiator tube, then flame stability is improved, but temperature distribution uniformity deteriorates
Solution Approach 1:
The invention applies local quality by creating different flow conditions in different regions of the combustion chamber. The flame holding member establishes a recirculation zone that maintains stable combustion locally, while the overall flow pattern ensures uniform heat distribution along the radiator tube. This local stabilization approach allows combustion to be terminated midway while maintaining temperature uniformity through controlled flow dynamics.
Solution Approach 2:
The invention introduces dynamic flow patterns through the flame holding member that create a recirculation zone. This dynamic structure allows the flame to be stabilized at a specific position while the circulating flow ensures uniform heat distribution along the tube, resolving the contradiction between flame stability and temperature uniformity.
3Reliability
If a tube-shaped flame is formed at a position separated from the radiator tube, then flame stability is improved, but heat extraction efficiency deteriorates
Solution Approach 1:
The invention ensures continuity of useful action by positioning the flame holding member and stable flame in direct contact with or adjacent to the radiator tube surface. This continuous contact maintains stable combustion while enabling efficient heat transfer from the flame to the tube, eliminating the energy loss associated with separated flame positions.
4Productivity
If the flow velocity of premixed gas is increased to improve combustion speed, then combustion efficiency is improved, but flame stability deteriorates
Solution Approach 1:
The flame holding member acts as an intermediary that decouples the relationship between gas flow velocity and flame stability. It allows high velocity gas flow to pass through while capturing and stabilizing the flame at a controlled position within the recirculation zone, enabling both high combustion speed and flame stability to coexist.
Solution Approach 2:
The invention creates a dynamic recirculation zone that adapts to varying gas flow velocities. The circulating flow pattern maintains flame stability across a range of velocities by continuously replenishing the flame zone with fresh mixture while removing combustion products, allowing the system to maintain stability even at higher combustion speeds.
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 design achieves stable flame formation and enhanced heating efficiency without increasing costs, allowing for efficient heat extraction and reduced NOx production, while also enabling application to low-pressure city gas lines by avoiding pressure loss and complex manufacturing processes.
Implementation Method 1
A stagnation point for combustion gas is formed in the combustion space and the flow of combustion gas in the combustion space is set to form a circulating flow about the periphery of the stagnation point
Implementation Method 2
a combustion burner is known in which combustion gas is combusted in an inner tube and a direction of flow is varied by collision of a jet of combustion gas with a shield surface disposed orthogonally thereto to thereby extract heat from the radiator tube
Implementation Method 3
a combustion heater that combusts a premixed gas of a fuel gas and combustion air
Data Source
AI summary
A combustion heater includes an inner tube having a supply passage for combustion gas in an inner portion, and an outer tube disposed to provide a separated combustion space in an outer periphery of the inner tube. A hole part for ejecting the combustion gas is formed on a tube wall of the inner tube and combustion gas is ejected with ejection characteristics such that circulating flow is formed on the periphery of a stagnation point. According to this combustion heater, a stable flame can be formed without increasing costs and the heating efficiency can be improved.