Muffler Acoustic Ray Deflection via Temperature Gradient
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Solution Overview
Problem
Conventional muffler designs fail to effectively reduce aircraft noise, particularly in the mid- to low-frequency range, due to limitations in sound absorption capacity, especially during aircraft takeoff and landing, where noise pollution is most significant.
Innovation Solution
The implementation of a muffler with a low temperature refrigeration system creating a temperature gradient between the inner and outer surfaces, deflecting acoustic rays towards a sound-absorbing structure on the inner surface, thereby increasing the sound absorption coefficient and enhancing noise attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acoustic lining is applied to the internal surface of the pipeline to reduce radiated engine noise, then noise reduction is achieved, but the sound absorption capacity is insufficient for mid- to low-frequency noise in high acoustic intensity environments
Solution Approach 1:
The patent changes the temperature parameter of the muffler system by introducing a refrigeration system that creates a temperature gradient within the muffler. The temperature inside the muffler is maintained lower than the outside temperature, which alters the acoustic ray propagation characteristics and improves sound absorption capacity for mid- to low-frequency noise.
Solution Approach 2:
The patent introduces a dynamic temperature control mechanism that actively maintains a temperature gradient across the muffler walls. The refrigeration system dynamically adjusts the internal temperature to optimize acoustic ray deflection and sound absorption under varying operating conditions.
2Reliability
If the depth of the air cavity of the sound-absorbing structure is substantially increased to enhance absorption of mid- to low-frequency noise, then sound absorption is improved, but the structural complexity and space requirements increase
Solution Approach 1:
Instead of increasing the physical depth of air cavities, the patent changes the temperature parameter to create a temperature gradient that deflects acoustic rays toward the sound-absorbing structure. This approach achieves enhanced sound absorption without increasing structural depth or complexity.
Solution Approach 2:
The patent replaces the mechanical approach of deep air cavities with a thermal field approach. By using temperature gradients to control acoustic ray propagation, the system achieves sound absorption enhancement without the mechanical complexity of deeper structures.
3Reliability
If a low temperature refrigeration system is introduced to create temperature gradient and deflect acoustic rays, then sound absorption coefficient is enhanced, but device complexity and energy consumption increase
Solution Approach 1:
The refrigeration system serves multiple functions: it cools the exhaust gases for environmental reasons and simultaneously creates the temperature gradient needed for acoustic ray deflection and enhanced sound absorption. This multi-functionality justifies the added complexity.
Solution Approach 2:
The patent converts the harmful heat in exhaust gases into a beneficial tool. By using refrigeration to create controlled temperature gradients, the thermal energy that would otherwise be wasted or harmful is transformed into a mechanism for enhancing sound absorption through acoustic ray deflection.
4Object-affected harmful factors
If temperature gradient is used to deflect acoustic rays toward sound-absorbing structure, then noise attenuation is enhanced, but use of energy increases due to refrigeration system
Solution Approach 1:
The refrigeration system provides dual benefits: environmental compliance by cooling exhaust gases and noise control by creating temperature gradients for acoustic ray deflection. This multi-functionality offsets the energy consumption through combined environmental and acoustic benefits.
Solution Approach 2:
The patent converts the energy required for refrigeration from a pure cost into a dual-benefit investment. The same temperature gradient that enables acoustic ray deflection and noise attenuation also serves to cool exhaust gases, transforming energy consumption into a productive environmental control function.
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 approach significantly enhances the muffler's noise reduction capabilities, achieving additional sound absorption and attenuation, transitioning the muffler's sound absorption capacity from 'less saturated' to 'saturated' or 'over-saturated', effectively reducing radiated noise and improving environmental noise control around airports.
Implementation Method 1
Acoustic ray deflection theory; deflecting the acoustic ray inside the muffler pipeline toward the external surface with the lower temperature resulting from the said temperature gradient according to Fermat principle
Implementation Method 2
sound-absorbing structure on the internal surface of the airflow pipeline; increasing the sound absorption coefficient
Data Source
AI summary
The present invention provides an acoustic attenuation based on sound ray deflection theory and a muffler. The method of the present invention provides a temperature gradient between the interior and the exterior of the chamber of the muffler through the low temperature refrigeration system, in which the temperature inside the pipe wall is higher than that outside the pipe wall. The said temperature gradient may deflect the acoustic ray towards the low temperature direction, so as to capture and reduce the noise. The muffler of the present invention comprises a muffler housing laid with a sound absorbing structure (4) on its internal surface, is characterized by the low temperature refrigerating system (2) which is fixed in the position corresponding to the sound absorbing structure (4) on the external surface of the muffler housing (1), covers at least 5% of the area of the external surface of muffler housing (1), and is used to realize quantitative control of the temperature gradient together with a temperature control system (3). The muffler of the present invention effectively improves the noise-absorbing effect of the prior muffler.