Low-Noise HVAC Airflow Design

Vehicle air conditioning system that reduces airflow noise while keeping compact size. The system has a narrow inlet section that widens downstream to prevent backflow and noise. A flow path width adjusting unit connects the inlet to the housing wall. It decreases width upstream of the narrow nose section. This matches the inlet width profile to gradually widen the airflow path. This prevents backflow and reduces noise compared to a sudden width change at the narrow nose.

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Automated bioprocess control system using Raman spectroscopy to monitor and optimize cell culture processes like bioreactors without invasive sampling. The system has a Raman spectrometer to continuously monitor cell culture parameters like glucose, lactate, ammonia concentrations inside the bioreactor. A controller uses the Raman data to autonomously adjust nutrient feed rates and other process parameters to maintain optimal conditions for cell growth and product quality.

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Centrifugal fan with improved airflow and reduced noise compared to traditional designs. The fan has multiple air inlets instead of just one. The main air inlet is at the top, but there are also secondary air inlets at the bottom. The impeller has a larger projection at the top than the main air inlet. This overlaps the secondary air inlets. This allows more airflow through the secondary inlets while preventing excessive noise from the larger main inlet. The secondary inlets have irregular shapes. The housing also has a shield to block some of the impeller edges. This further reduces noise. The fan housing, impeller, and support structure are configured to balance airflow, pressure, and noise.

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Air conditioner that reduces noise and odor during drying mode by sequentially turning off fans after cooling instead of running them at high speed. The air conditioner has multiple fans to blow air through the heat exchanger and outlets. After cooling, all fans turn on for drying, then they are sequentially turned off. This prevents loud noise and mold release when fans stop. Sensors monitor indoor temp, heat exchanger temp, and humidity to determine when drying is complete.

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A blower assembly for vehicle HVAC systems with improved airflow and noise reduction. The blower assembly has a blower wheel inside a scroll housing with annular scroll channels defined by inner and outer ring walls. The blower wheel has blades and ribs in the inlet channel between the inner and outer ring walls. This configuration draws air axially into the scroll channels and discharges it radially. The inner ring wall between the channel walls reduces airflow leakage. The scroll channels also help quiet the blower.

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Compact air plenum silencer for HVAC systems that reduces noise levels from return air ducts without requiring long silencers or elbows. The silencer is installed in the return air inlet and has multiple baffles inside with perforated volumes. The baffles are fixed to the housing and have perforations that allow airflow but also redirect sound waves. The baffles are positioned on opposite sides of the housing to provide noise attenuation in both directions.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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.

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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.

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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.

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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.

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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.

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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.

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