Noise control during burner operation requires a comprehensive design approach encompassing sound source suppression, propagation path blocking, and structural optimization, employing multi-dimensional technical means to achieve noise reduction goals. Sound source suppression is the core of noise reduction and must begin with the burner's internal structure. For example, optimizing the burner's nozzle design by using porous or flower-shaped gas caps instead of traditional single-hole nozzles can significantly reduce jet noise by altering the initial characteristics through jet interference. Simultaneously, adjusting the gas pressure and gas cap outlet velocity prevents turbulence noise caused by excessive flow velocity. Furthermore, rationally controlling the combustion heat load to avoid localized overheating and combustion instability is also crucial for reducing combustion noise. For handling large flow rates of gas, increasing the number of burners to distribute the heat load, rather than simply increasing the power of a single burner, can reduce the overall noise level.
Propagation path blocking requires a combination of sound absorption, sound insulation, and silencing technologies. Installing sound-absorbing components around the burner is a direct and effective method. For instance, lining the sidewalls of the combustion chamber with porous sound-absorbing materials, such as glass wool or slag wool, utilizes the friction and viscous resistance of the material's internal pores to convert sound energy into heat energy. For high-frequency noise, high-sound-absorbing materials such as ultra-fine glass wool can be used, with a thickness meeting certain standards to ensure sound absorption in the target frequency band (e.g., 125-500Hz). Sound insulation design requires blocking noise transmission through physical barriers, such as installing a soundproof enclosure for the burner, with the inner wall lined with porous materials and the outer layer made of high-density steel plate or concrete, forming a double sound insulation structure. To prevent noise transmission through pipes, silencers can be installed on the exhaust pipes, using changes in acoustic impedance to reflect some sound waves back to the sound source, or by altering the sound wave propagation path through side branch pipes, achieving noise reduction.
Structural optimization needs to address both the overall burner layout and material selection. First, optimize the burner geometry to avoid sharp edges or protruding structures that cause sound wave reflection and resonance. For example, a streamlined design reduces airflow resistance, or the volume and shape of the combustion chamber are adjusted to make the sound wave propagation path smoother, reducing noise superposition effects. Second, select low-noise drive devices and fans to avoid mechanical noise generated by direct motor connection. For example, using belt drives or couplings and equipping the burner with a low-speed impeller reduces rotational noise at its source. Furthermore, strengthening the burner's structural rigidity by adding support beams or reinforcing the frame reduces low-frequency noise caused by vibration.
Targeted designs are necessary for specific noise types. For instance, for low-frequency "roaring" noise caused by combustion instability, the deflection velocity can be adjusted using a double-orifice plate method to expand the absorption frequency range and suppress thermoacoustic instability. This method uses a double-orifice plate device to adjust the deflection velocity separately, allowing the damper to operate at a selective target frequency, achieving wideband noise reduction. For high-frequency jet noise, guide vanes or rectifiers can be installed at the burner outlet to ensure more uniform mixing of fuel gas and air, reducing turbulence. Simultaneously, optimizing the burner's installation location to avoid proximity to walls or reflective surfaces reduces the superposition of reflected sound waves.
Material selection is crucial for noise reduction effectiveness. In high-temperature environments, heat-resistant sound-absorbing materials, such as ceramic fibers or aluminosilicate cotton, must be used to ensure they do not fail under long-term high-temperature conditions. For soundproof enclosures, the outer material must balance sound insulation and fire resistance, such as using galvanized steel or stainless steel sheets, with the inner layer filled with fire-resistant sound-absorbing cotton. Furthermore, surface treatment of the materials must be considered; for example, covering the sound-absorbing material with a perforated protective panel protects the material while improving sound absorption.
In practical engineering, noise reduction design must consider the burner type and application scenario. For example, industrial furnace burners, due to their high power and heat load, require composite noise reduction technology, while simultaneously optimizing the burner structure and installation location. Household gas stove burners, on the other hand, prioritize size and cost, and noise reduction can be achieved by optimizing the burner hole design and adding small silencers. Regardless of the scenario, on-site testing and simulation analysis are necessary to verify the noise reduction effect and ensure that the design parameters meet actual requirements.
Noise control during burner operation requires multi-dimensional technical means, including sound source suppression, propagation path blocking, structural optimization, targeted design, material selection, and scenario adaptation. From the design of the fire hole to the application of sound-absorbing materials, from the selection of the transmission device to the optimization of the overall layout, every step requires meticulous design in order to build a complete noise reduction system that meets the noise control needs of different scenarios.
