Low-Noise HVAC Airflow Design

Reducing airflow noise in a centrifugal compressor with a casing treatment that involves a specific arrangement of spoke and wing-like features in the compressor housing. The spoke portions connect the inner wall of the air intake hole to an annular portion inside the hole. The wing-like features extend from a tubular portion upstream of the annular portion. The spoke and wing features are arranged at matching positions around the annular portion. This forms sub-flow paths that branch off the main flow path, join back together, and engage with the annular portion. Equalizing the spoke and wing positions prevents flow separation and irregularities that can cause noise.

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A centrifugal blower with reduced noise and simplified manufacturing. The blower integrates the blades, shroud, and impeller cup into a single component. This allows a unique impeller cup shape that enables a zero-degree slope angle between the shroud and impeller. This eliminates undercut regions that can generate noise from flow separation. The integrated component simplifies molding compared to separately molding the parts. The impeller cup fits onto the main plate after molding.

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Blower fan design to reduce noise by preventing separation of airflow from the blades. The fan has blades with serrations along the leading edge from the center to the tip. This reduces separation of airflow from the negative pressure side of the blade. Additionally, the blade shapes direct the airflow towards the separation limiting structures of adjacent blades on the rear side. This further reduces airflow separation at the blade base.

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Air amplifier for fan assemblies like bladeless heaters/coolers to improve airflow, efficiency and noise reduction. The amplifier has an inlet to connect to the fan, an airflow cavity with walls, and a lip at the front wall edge. This lip partially obstructs airflow from the exhaust outlet. This focuses and amplifies the airflow by creating a higher pressure in the cavity compared to the fan exit. It enables improved airflow, efficiency and noise reduction in a low pressure system.

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Air vent for vehicles that provides quieter airflow compared to conventional vents. The vent has a housing with an air inlet and outlet, a rigid air directing body inside, and an actuator containing a shape memory alloy element. The actuator pivots the directing body to change the airflow direction. The shape memory alloy element allows quieter operation compared to electric motors. The directing body has a convex surface that engages a concave surface on the body. The concave surface faces the inlet and the convex surface faces the outlet. This allows pivoting the directing body without moving parts that create noise.

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A noise-reducing and nonuniform tip clearance structure for centrifugal compressors that reduces aerodynamic noise compared to traditional uniform tip clearance. The impeller tip clearance gradually decreases from the leading edge to the trailing edge, with a higher rate of decrease near the leading edge. This reduces radial backflow and cross-blade flow along the clearance that can increase flow loss and noise. The nonuniform clearance distribution also reversely compensates for impeller deformation under load.

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Compact, high efficiency residential HVAC air handler with close coupling of components for improved performance and noise reduction. The air handler has a mixed-flow fan, a wide-angle diffuser, and two high resistance media (like filters and heat exchangers) placed immediately upstream and downstream of the fan and diffuser. The media are positioned close to the fan and diffuser blades/vanes, within specific distances to leverage synergy between the components. The close coupling improves efficiency and reduces noise compared to conventional HVAC designs with standalone components.

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<div class="section abstract"><div class="htmlview paragraph">This paper presents a fully parallelized Computational Acoustics (CA) module, integrated within the Simerics-MP+ platform, developed for prediction of noise source power and far-field propagation across range Fluid Dynamics (CFD) applications. Utilizing Ffowcs Williams-Hawkings (FWH) acoustic analogy, CA module seamlessly integrates with existing CFD workflows, offering minimal computational overhead less than 5% increase in runtime. Extensive validation has been conducted against analytical, numerical, experimental data various scenarios, including monopole dipole emissions, flow around slender bodies, circular cylinders aero-propellers. These studies underscore reliability framework accurately identifying sources assessing impact design modifications, significantly reducing need expensive physical prototyping industries such as automotive aerospace.</div><div paragraph">Building upon these foundational capabilities, study extends application to challenging task simulation axial fans, commonly empl... Read More

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<div class="section abstract"><div class="htmlview paragraph">This study evaluates the effectiveness of two hybrid computational aeroacoustic methodsLighthill wave model and perturbed convective modelin simulating HVAC duct noise in automotive industry. Using component-level acoustic testing a Ford duct, simulations were conducted at varying airflow rates to assess accuracy both models predicting noise. The Lighthill model, suitable for analysis regions outside turbulent flow areas, showed good correlation with experimental data, especially frequency range 100 Hz5000 Hz, but sometimes struggled pseudo-noise effects low frequencies near regions. which is anywhere domain, underpredicted sound pressure levels as well. Both high-frequency (>5 kHz) due insufficient mesh time-step sizes. Despite these limitations, provided better overall agreement results. also identified resonance peak 160 captured offering valuable insights further optimization. These findings underscore potential improve design quieter systems, enhancing vehicle comfort customer satisfaction.... Read More

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Blower design with a diffuser to convert the direction of airflow discharged by the fan into ascending airflow. This allows the blower to efficiently move air vertically without needing a separate upward fan or ducting. The diffuser extends vertically from the fan outlet and guides the air upward. It reduces noise and flow separation compared to conventional rising airflow generators. The diffuser shape and angles are optimized to balance noise reduction and efficiency.

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Cabinet air conditioner design that reduces noise by buffering the airflow out of the heat exchanger before it enters the ducts. The air conditioner has a shell with an air inlet in the rear and an air outlet in the front. The airflow path is split into two sections. The heat exchanger is between the cross-flow fan and rear shell. The air outlet of the heat exchanger is not opposite the air inlet of the through-flow duct. This causes the air to turn or shift as it leaves the heat exchanger before entering the ducts. This buffering reduces the peak air speeds and noise at the outlet.

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A codesigned shroud for a chassis with components and fans that balances airflow for cooling and attenuates acoustic energy to protect sensitive components like hard drives from fan noise. The shroud has channels aligned with the airflow directions, with baffles in a noise attenuation channel perpendicular to the flow. The baffles have absorbent material to block direct acoustic paths. This balances cooling airflow while preventing noise from fan vibrations and flow turbulence.

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A fan and air conditioner design with improved airflow and reduced noise compared to conventional designs. The fan has a two-section volute tongue that steps in height. The first section extends along the air duct opening and the second section extends from the end of the first section. This smooths the airflow transition and reduces vortex formation compared to a single tongue. The air conditioner has a matching stepped volute tongue in the duct cover and seat. This joint configuration improves airflow in the duct and reduces noise compared to conventional ducts.

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Air passage silencer with improved low frequency attenuation and reduced wind noise compared to conventional expansion type silencers. The silencer has a tapered opening structure at the expansion to outlet connection, surrounded by a rear space. A porous material is added in the rear space opening to absorb sound. This provides resonance in the tapered space for low frequency attenuation, without backflow turbulence. The tapered opening reduces wind noise compared to a sudden expansion. The expansion size, tapered shape, and rear space dimensions are optimized for performance.

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Heating, ventilation, and air conditioning (HVAC) terminal unit with improved airflow distribution and noise reduction compared to traditional units. The terminal unit has a sound attenuator positioned opposite the air inlets that directs return airflow into the unit. This balances the airflow distribution to the blowers and reduces noise compared to uneven airflow. The attenuator has an inlet facing the return air inlet and outlet into the unit. Baffles inside the unit further direct the airflow. This balanced airflow reduces blower speeds, pressure losses, and noise compared to uneven flow.

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Air conditioner design with reduced noise by preventing vortex formation in the air ducts. The ducts are split using a dividing piece near the impeller inlet. This divides the airflow entering the impeller into two streams, one from each duct half. The stream entering from the second duct half passes through an angle formed by the duct shape, preventing vortex formation. This prevents pressure pulsations and noise caused by vortex interaction in the ducts.

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Fresh air module for air conditioners that reduces noise compared to conventional modules. The module has a housing with an inlet and outlet, a fan assembly with a motor and wind wheel, and a partition between the motor and fresh air duct. The motor is outside the duct in a separate compartment. This isolates the motor noise from the airflow, preventing amplification and reducing overall noise.

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Air outlet panel for floor type indoor air conditioners that improves airflow efficiency and reduces noise compared to conventional designs. The panel has a strip-shaped plate with a grid section for high airflow and a weaker air outlet section. Sealing strips around these sections weaken flow to adjacent areas, directing more air through the intended outlet. This prevents unnecessary flow losses and noise. The sealing strips also have fillers and brushes to further regulate airflow. The panel can switch between the grid and weaker outlet sections for different applications.

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Air port device and air conditioning unit with reduced noise. The air port device has a silencing cover inside the air duct between the inlet and outlet. The cover has holes for airflow and disperses it to reduce turbulence. It also has a cone to guide air uniformly. This reduces noise by scattering and refracting sound, lowering flow velocity, and absorbing noise with cotton.

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Air duct design for air conditioners that reduces vortex wind phenomenon, noise, and improves user experience compared to conventional spiral case air ducts. The duct has detachable volute covers and seats that form extendable tongues to gradually expand airflow from the inner duct to the outer duct. This reduces vortices and noise compared to sudden expansion in conventional ducts. The outer tongue extends further than the inner tongue and the outer duct opening is smaller. The tongues' lengths and angles are balanced to further reduce noise.

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