Low-Noise HVAC Airflow Design

Centrifugal fan designs that reduce noise and improve airflow in confined spaces like laptops. The fan housing has features like angled cutwaters, slotted cutwaters, and acoustic dampening materials to mitigate tonal and broadband noise. These fan housing concepts were tested and showed significant noise reduction and flow improvement compared to standard fans. The designs involve modifications like angled cutwaters that extend at acute angles from the fan base, slotted cutwaters, and acoustic dampening materials in the housing.

Source

A low noise vehicle fan assembly for air distribution in cabins like aircraft that uses toroidal shaped fan blades instead of conventional airfoil blades. The toroidal shape forms loops that reduce noise compared to traditional fan blades. The loops create a low pressure zone behind the blade tips that captures airflow, reducing turbulence and noise. The fan assembly also encloses the motor and impeller in a case around the toroidal blades to further reduce noise transmission.

Source

Outdoor unit for refrigeration systems that reduces air resistance while rigidly supporting the fan motor to suppress noise. The unit has a motor support plate with a reinforced area around the fan motor insertion hole. The reinforced area is created by bent plates that extend from the inside edge of the hole. These bent plates reinforce the plate around the fan motor without increasing its front-rear projection. This provides sufficient rigidity to support the fan motor without narrowing the airflow passages.

Source

Air diffuser for a transport refrigeration unit evaporator that improves airflow efficiency and reduces noise compared to conventional designs. The diffuser has a unique shape with angled walls and turning vanes that gradually increase in depth as the airflow turns. It also has guide vanes and a finger guard at the outlet to prevent fingers from entering. The diffuser is molded as a single piece and can accommodate multiple fans. This customized airflow path reduces velocity, aerodynamic losses, and impingement.

Source

A blower device for a heating, ventilation and air conditioning (HVAC) system in a vehicle that improves airflow and reduces noise. The blower has an uneven number of blades and vanes to create a swirling airflow pattern. The blower housing has an inlet with a preswirler of unevenly shaped vanes that slope toward the blower wheel. This uneven configuration causes the air to swirl as it enters the blower, which reduces turbulence and noise compared to a symmetrical swirler. The blower blades themselves can also be unevenly spaced.

Source

A lubrication system for a pump drive that prevents direct contact between the motor and housing to improve operation and lifespan. The system uses a lubricant reservoir, conduit, and sensor. The reservoir stores lubricant, the conduit directs lubricant into the motor housing, and the sensor monitors the reservoir level. If the level drops below a threshold, motor operation is reduced to avoid dry running. This prevents motor-housing contact by keeping the motor submerged in lubricant.

Source

Centrifugal blower design with reduced surge and clogging issues. The blower has an impeller and a scroll casing. The scroll casing has a tongue to guide the gas flow and a peripheral wall with a first and second planar portions. The clearance between the wall and impeller is smallest at the second portion. This configuration prevents gas stagnation and turbulence at the narrowest part of the passage, reducing surge and noise. The blower also has more blades (60 or more) to increase low flow static pressure.

Source

This work is devoted to the design and evaluation of a low-noise outlet guide vane (OGV) aiming reduce rotorstator interaction noise using leading-edge serrations tested on ECL5 ultrahigh-bypass-ratio model in PHARE-2 rig at Ecole Centrale Lyon. First, radially varying 2D proposed evaluated by means fast analytical prediction tool strip approach. Then, an iterative process combining 3D Reynolds-averaged NavierStokes (RANS) calculations with in-house modeler carried out achieve suitable geometry while minimizing aerodynamic penalties. Following this process, high-fidelity simulations based lattice Boltzmann solver are performed assess sound power level reduction achieved serrated OGV (by comparison untreated baseline case primarily tested). Due low-compressibility assumptions present method, limited reachable higher regime (45% nominal rotational speed). Hence, available numerical predictions compared experimental data terms both acoustic performances. A rather good agreement obtained reductions up 3 dB from broadband intake radiation 6 bypass duct considered operating points. I... Read More

Source

Ventilation fan with blades that change shape along their length and have a capping plate covering the blade ends near the fan inlet. The blades have chords that taper inward or outward towards the inlet, rather than maintaining a uniform width. This allows for better airflow and reduced noise compared to conventional fans with uniform blades. The capping plate prevents debris from entering the fan housing through the blade ends. The blades also have a secured portion attached to the hub and a free portion extending outward. This provides flexibility in blade design without compromising structural integrity.

Source

An arrangement to reduce noise at the air inlet of a blower ventilator like a respirator without using foam or other soft materials. The arrangement has a connecting element with an inlet and outlet, and at least one labyrinth element with parallel channels. The labyrinth element fills at least 40% of its volume with channels that guide air and deflect noise. The connecting element and labyrinth elements are configured so air flows in parallel axes with a 90 degree deflection between the elements. This routing reduces noise by reflecting and deflecting the operating noise.

Source

Compact sound device that mitigates noise near airflow openings like duct endpoints using acoustic resonance. The device surrounds the opening and has a cavity with a partition. The cavity reflects sound waves at target frequencies to mitigate noise. This compact design saves space compared to devices inside ducts and avoids aerodynamic disruption. The cavity lengthened by the partition enhances resonance.

Source

Efficient attenuation of low-frequency sound (<1000 Hz) while maintaining unrestricted airflow remains a long-standing pursuit in noise control engineering. Here, ventilation barrier is integrated with Helmholtz resonator and an open channel. A density-based topology optimization approach employed to distribute material within the resonant cavity, effectively reducing at target frequencies. For frequencies 550 Hz, 500 450 400 350 optimized designs achieve transmission losses exceeding 25 dB. Multiple solutions for same show minimal variation performance. Sound pressure particle velocity distributions are analyzed reveal insulation mechanisms units. Acoustic experiments validate designs, results agreement numerical calculations. Furthermore, 48.1% channel area maintained, ensuring efficient airflow. Ventilation tests confirm effective air circulation, demonstrating advantages over conventional barriers expanding potential applications diverse scenarios.

Source

Axial fan assembly for heating, ventilation, and air conditioning (HVAC) systems that can be used in air handling units while using less energy and generating lower noise compared to traditional blowers. The assembly includes an axial fan, inlet ring, stator, outlet ring, and fan deck. The components are arranged to direct air through the assembly, straighten the flow, and prevent turbulence. This improves fan efficiency and reduces noise. The assembly can be used in HVAC units to circulate air while consuming less energy than traditional blowers.

Source

Centrifugal fan design that improves efficiency and reduces noise compared to conventional fans. The fan blades have outlet edges shaped to create progressively larger gaps between them. This gradual expansion of air channels reduces velocity and mitigates expansion losses. The fan housing has transition portions on the sidewalls that extend radially outward. These transitions lead to openings between the end walls that gradually increase in size. This gradual expansion reduces velocity and pressure drop at the fan outlet. The fan motor assembly further compresses the size by integrating the motor into the fan wheel, reducing overall length.

Source

Composite material for acoustic applications like air ducts and hushpanels that provides high acoustic performance, light weight, and ease of assembly. The composite has layers of fibrous materials like nonwovens sandwiched between layers of nonwovens. This layering creates a multi-acoustic impedance mismatch profile that amplifies noise reduction compared to standalone layers. Overmolding onto specific areas allows attaching features without filling the entire composite. The composite can be thermoformed into complex shapes. The fibrous layers have controlled porosity for air permeability and sound absorption. The layering enables customization of acoustic properties while maintaining light weight and assembly benefits.

Source

Centrifugal air fan with reduced noise and improved efficiency. The fan impeller has blades with decreasing thickness towards the outer circumference. This gradual vane taper reduces rapid pressure fluctuations and increases airflow volume compared to uniform thickness blades. When air flows back into the impeller from the bell mouth, it collides with the inner blades at lower speeds, preventing noise and flow separation.

Source

Guiding mechanism for range hood centrifugal fans that improves airflow efficiency and reduces noise. The mechanism guides the airflow as it exits the fan's volute to make a turn before discharge. This reduces energy loss and aerodynamic noise compared to abrupt turns. The mechanism is a curved shape with a smooth internal flow path at the fan's rear outlet. This allows the airflow to smoothly transition and turn without turbulence.

Source

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.

Source

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.

Source

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.

Source