Pulse Combustion Heat Exchanger with Cooled Transition Sections
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Solution Overview
Problem
Pulse combustion heat exchangers face challenges in maintaining structural integrity and minimizing thermal stress at elevated temperatures, while ensuring continuous operation and reducing maintenance in industrial processes.
Innovation Solution
The design incorporates a pulse combustion heat exchanger with a configuration that includes an oxidant and fuel inlet section, a mixing section with aerovalves, a combustion section, a heat transfer section with resonance conduits, and transition sections with coolant paths, along with a decoupler section to manage thermal stress and facilitate efficient heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the heat exchanger operates in an elevated temperature environment (1,000 to 1,500° F.), then heat transfer efficiency is improved, but thermal stress and creep increase, compromising structural integrity
Solution Approach 1:
The heat exchanger is divided into multiple tubesheets (first, second, and third tubesheets) that create separate zones for hot gas flow and coolant flow. This segmentation allows different parts of the structure to experience different thermal conditions, reducing overall thermal stress on the system while maintaining efficient heat transfer in the combustion zone.
Solution Approach 2:
A coolant system acts as an intermediary between the high-temperature combustion gases and the structural components. The coolant flows through channels in the tubesheets and absorbs heat, protecting the structural integrity of the heat exchanger while allowing it to operate at elevated temperatures for efficient heat transfer.
2Device complexity
If conventional combustion-based fire tube heat exchangers are used, then structural simplicity is maintained, but heat transfer resistance is high and thermal efficiency is reduced
Solution Approach 1:
The heat exchanger utilizes periodic pulsating combustion instead of continuous steady combustion. This periodic action creates oscillating flow patterns that enhance heat transfer coefficients and reduce thermal boundary layer resistance, significantly improving thermal efficiency compared to conventional continuous combustion systems.
Solution Approach 2:
The system changes the combustion parameters by operating in a pulsating regime rather than steady state. The periodic variation in combustion intensity and gas flow creates dynamic heat transfer conditions that reduce thermal resistance and improve overall heat transfer efficiency.
3Productivity
If the heat exchanger is designed for continuous operation, then productivity is improved, but maintenance requirements increase and shut-down periods are needed
Solution Approach 1:
The coolant system serves as a protective cushion that prevents excessive thermal accumulation in the structural components. By continuously removing heat during operation, it reduces thermal fatigue and extends the time between maintenance intervals, enabling longer continuous operation before shutdown is required.
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 enhances heat transfer efficiency, reduces thermal stress, and maintains continuous operation by effectively managing thermal loads and coolant circulation, thereby improving the structural integrity and lifespan of the heat exchanger.
Implementation Method 1
a mixing section (300) including one or more aerovalves (A, A′, A′′, A′′′, AN, AN+1) that are configured to accept and mix oxidant (1A1) from the oxidant inlet section (100) with fuel (1A2) from the fuel inlet section (200)
Implementation Method 2
a combustion section (400) configured to receive and combust the oxidant and fuel mixture (1A3) from the mixing section (300) to produce a pulsating combustion stream (1A4)
Implementation Method 3
a heat transfer section (500) configured to receive the combustion stream (1A4) from the combustion section (400), the heat transfer section (500) including one or more resonance conduits (502, 502A, 502B, 502C, 502D, 502E) that are configured to transfer heat from the combustion stream (1A4) to an energy sink (V108)
Implementation Method 4
a first transition section (450) positioned between the combustion section (400) and the heat transfer section (500), the first transition section (450) comprising a first coolant path configured to receive a first coolant (451)
Data Source
AI summary
A pulse combustion heat exchanger having a longitudinal axis is configured to accept oxidant and fuel and output a cooled combustion stream. The pulse combustion heat exchanger includes an oxidant inlet section that accepts oxidant, a fuel inlet section that accepts fuel, a mixing section that mixes oxidant with fuel, a combustion section that receives the oxidant and fuel and produces a pulsating combustion stream, and a heat transfer section configured to receive the pulsating combustion stream, the heat transfer section includes one or more resonance conduits. Coolant is employed at a plurality of longitudinally spaced-apart transition sections to remove heat.