The rear guide vane is a critical component influencing the aerodynamic and acoustic performance of mixed-flow fans. Inspired by owl wing morphology, the thickness distribution from a long-eared owl wing at the 40% spanwise section and applied it to biomimetic guide vane blades, using the prototype vanes' mean camber line as the baseline. Experimental measurements under identical airflow conditions showed that the fan equipped with biomimetic vanes achieved a 1.4% efficiency improvement and a 0.8 dB noise reduction compared to the prototype. Numerical simulations revealed no significant low-velocity zone near the biomimetic vane trailing edge, with a more uniform flow distribution and effective suppression of flow separation and vortex shedding. The results demonstrated enhanced matching between the impeller and guide vane, significantly reducing impeller outlet flow impact on the vane leading edge. Furthermore, noise analysis confirmed reductions in both broadband and discrete noise within the mid-to-low frequency range, achieving dual objectives of higher efficiency and lower noise emission.

The fan wheel of the outdoor unit in air conditioning systems directly impacts the energy efficiency, stability, noise levels, and environmental performance of the system, and also a key factor to improve the overall performance of air conditioning systems. Based on the four-boundary theory of the impeller, this study systematically optimizes the outdoor unit's fan wheel through a combination of numerical simulations and experimental research. The results demonstrate that the flared design at the leading edge of the blade effectively controls the top and bottom rotating vortices, increasing the fan pressure and air volume by approximately 10% at the same rotational speed while reducing noise by 1.3 dB(A) at the same air volume. Additionally, the backward-curved design in the region of 2% of the impeller diameter at the blade tip significantly suppresses the tip vortex backflow effect and pressure pulsation, maintaining the same air volume at the same rotational speed while reducing noise by 0.5 dB(A)~1 dB(A) at the same air volume. The two optimization schemes exhibit a synergistic effect; when applied simultaneously, they achieve a noise reduction of 1.7 dB(A)~2.3 dB(A) at the same air volume, with a 3 dB(A)~4 dB(A) reduction in the peak of low-frequency rotational noise, significantly improving the acoustic quality.

With the rapid growth trend of inverter air conditioners, the proportion of DC motors in air conditioners will continue to increase. Improve the cost performance of DC motors for air conditioners is very crucial. Therefore, the high power density and low noise design of air conditioning DC motor is deeply studied. Firstly, the fully segmented low leakage flux rotor technology is adopted to increase the motor power density and reduce the electromagnetic cost of the motor. Secondly, for the common 6fe, 12fe, and 14fe noise problems of air conditioner outdoor units, the mechanism is analyzed one by one, and the corresponding influencing factors are identified. Then, the electromagnetic structure is optimized to eliminate or weaken these influencing factors. Finally, through sample production, it is verified that the above technologies can increase the motor power density while reducing the single-unit noise by 3 dB(A) to 4 dB(A) compared to traditional motors, and the entire machine has no abnormal noise throughout the process. The research results provide reference significance for the subsequent design of high power density and low noise motors.

The IH rice cooker of our company has relatively high working noise, which affects the user experience. To address the noise issue, a research project was initiated. Firstly, the mechanism of noise generation in IH electric cookers was analyzed, and verification tests were conducted using the single variable method, and the test data were organized and analyzed with mathematical tools. Research findings indicate that the main factor affecting the operational noise of IH rice cooker is the noise generated by the fan, and improving the performance of rice cooker requires a balance between reducing the overall temperature rise AD value and fan noise; The fan's rotational speed is the main factor affecting the overall noise of the machine, while the tip clearance and installation position of the fan have relatively minor impacts; The main factors influencing the temperature rise AD value of IGBT components are the fan's rotational speed, tip clearance, and installation position. The experimental tests of the hand-built prototype show that, while keeping the shape of the fan unchanged and reducing the fan speed to 2600 r/min, setting the the blade tip clearance was 1 mm, and the fan position was lowered by 2 mm, the noise level of the rice cooker and the AD value of IGBT temperature rise were optimized to 45.45 dB (A) and 74.17 ℃ respectively, with significant noise reduction effect. . The research results have certain guiding significance for the developmentand optimization of IH electric rice cookers.

Research focuses on the noise of light commercial refrigeration compressors. By comparing the noise spectrum and frequency modes of the shell, the direction for improving noise level of a certain frequency is identified. By Testing and comparing the noise spectrum, shell mode and the frequency results of the A-23cc compressor, the frequency of 2500 Hz was selected as the noise optimization target. In response to the characteristic of the highest excitation amplitude of 2600 Hz in the shell mode, which directly affects the overall noise of 2500 Hz, the shell will be changed as the improvement target. By moving the position of the shell welding strip downwards, the modal excitation peak of the shell was shifted from 2600 Hz to 2800 Hz, thereby reducing the impact on the noise spectrum of 2500 Hz. Compared with the results of the overall noise test before and after the improvement of the shell mode, the noise at 2500 Hz decreased by 6.1 dB(A), and the compressor overall noise decreased by 3.0 dB(A).

The centrifugal cooling system of the blender has a significant impact on its performance, especially on the temperature rise of the motor and electronic components on the circuit board. To improve the performance of the blender's centrifugal cooling system and reduce the temperature rise of core components, thereby extending the blender's service life, computational fluid dynamics and experiments were used to reconstruct and optimize the collector, volute, and blades of the centrifugal cooling system for a specific blender. The final reconstruction plan reduced backflow at the collector inlet, improved the diffusion capacity of the volute, and enhanced the working capacity of the blades. Experiments showed that the new centrifugal cooling system increased outlet flow by 16.3%, reduced motor temperature rise by 9.6 °C, and decreased overall aerodynamic noise by 1.1 dB. Provide theoretical and simulation guidance for the design and optimization of subsequent blender cooling systems.

Currently, performance testing standards and methods for room air conditioners are based on fixed operating points. The units under test are placed in a constant temperature and humidity laboratory, which differs significantly from actual operating conditions. Additionally, during the test, the air conditioner operates with a locked frequency, preventing the assessment of its frequency adjustment capabilities and failing to accurately reflect real performance. In order to solve the problems of the existing test methods, the methods and standards for air conditioning performance testing in various countries are in the direction of transition to dynamic testing. Based on the typical international CSA SPE-07:23 dynamic testing method. Proposes a program for the renovation of air enthalpy testing facility suitable for dynamic testing in terms of equipment configuration, data acquisition system, software calculation and control system, etc., and carries out experimental research and validation of the facility's renovation and dynamic testing. The results show that the dynamic following accuracy of the dry bulb temperature of the renovated facility does not exceed 0.3 ℃, and the dynamic following accuracy of the wet bulb temperature does not exceed 0.2 ℃.

The Eulerian-Lagrangian method was used to simulate the cooking oil fume diffusion and range hood capture process in the semi-enclosed kitchen room. Considering the effects of pressure pulsation and asymmetric distribution at the inlet of range hood caused by the periodic rotation of the impeller, the transition model is used to simulate. Considering the influence of heat radiation of the pot and burning waste gas to the movement of the cooking oil fume, some microscopic forces, such as thermophoretic force, Brownian force and Saffman lift, were used to describe the thermal movement of Mico-nanometer cooking oil fume particles. Firstly, the cooking oil fume state of simulation and experiment at different times is compared to verify the validity of the simulation method, and the phenomenon of cooking oil fume escape may occur is simulated and analyzed. Subsequently, analyzed the velocity and temperature distribution of cooking oil fume at different height locations in the cooking zone, and discussed the magnitude of various forces on cooking oil fume particles in the range of 0.0001 μm~10 μm at two typical locations, where near the pan and at the range hood inlet, revealing the reasons that drive the movement of cooking oil particles in different forms and with different sizes. Finally, explained the various cooking oil fume statuses presented earlier from the view of drag force distribution, proving that drag force is the primary factor influencing the motion of inhaled cooking fume particles. Provides theoretical insights into the mechanisms of cooking oil fume diffusion and the improvement of exhaust range hood capture efficiency.

With the growth of the high-net-worth population, traditional clothing care methods are no longer able to meet people's pursuit of quality. Intelligent clothing care technology can intelligently match care programs by accurately identifying clothing materials, satisfying the demand for high-quality care. This article establishes a clothing material recognition method based on deep convolutional neural network image recognition. It first recognizes the type of clothing and then further identifies the material of the clothing, achieving fast and accurate material recognition and clothing classification. Testing was conducted on over 4000 images of clothing taken in a clothing care cabinet according to the test script. The results show an accuracy of 92.06% in clothing type classification, 94.00% in material classification, 87.27% in identification accuracy, and 100.00% accuracy in cases with no clothing identified. This clothing material recognition method exhibits high accuracy and strong generalization ability, can providing technical support for intelligent clothing care programs, possessing broad application prospects.

The heat dissipation speed of the compressor compartment determines the refrigeration effect of the refrigerator. Takes the compressor compartment of a free built-in refrigerator as the research object, and proposes to divide the area according to the function of the compressor compartment, divide the space of the refrigerator compressor compartment into regions, and model the data to establish a parameterized compressor compartment model. Using a mathematical model to transform the physical model of the compressor compartment into a mathematical model of the heat load of the entire machine and the components in the compressor compartment can increase the power consumption level by 12.65%. In order to solve the problem of difficult heat dissipation when the refrigerator is embedded and installed, an independent air duct at the bottom of the compressor compartment is designed to accelerate the heat exchange between the heat source and the cold air, and the air circulation efficiency is increased by 3%. In order to further improve the heat exchange efficiency in the press, the solution guide regarding the placement angle of the air flow plate, under the same operating conditions of the refrigerator, when the air flow plate is placed at an angle to increase the air inlet area, the air volume can be increased by 0.42%.

In general, rigid polyurethane foam with an isocyanate index of 105-115 is used in the production of refrigerator doors in order to ensure the thermal insulation, strength and aesthetics required for the quality of refrigerator doors. Rigid polyurethane foam with a high isocyanate index of 120~130 was used for refrigerator doors, which is partly used in isocyanate technology, which is commonly used in building material panels, and related experiments proved that the deformation could be reduced by 33% without affecting the thermal insulation performance of the foam, and it is proved that the generation and attachment of an isocyanurate group inside the rigid polyurethane foam can improve the mechanical strength of the foam and suppress the deformation of the door. Finally, verified the experimental results of the method for determining the physical strength of the mechanism.

Disinfection cabinet is a tool for disinfection and storage of family tableware. In addition to paying attention to its disinfection effect, the storage and storage experience is also one of the most concerned factors for users. Among them, bowl basket design has a significant impact on product experience and storage effect, but the current industry lacks in-depth research on the design of disinfection cabinet bowl basket, and an evaluation model based on the user perspective is needed as a similar "North star" indicator to guide the design of disinfection cabinet bowl basket. Questionnaire, desktop research, observation and other user experience methods were used to build an index evaluation system based on structure recognition, placement flexibility, owl and basket tolerance, convenience and placement stability. On this basis, the analytic Hierarchy process (AHP) was used to calculate the index weight, and the fuzzy comprehensive evaluation method was applied to compare and evaluate various types of bowls and baskets. The evaluation results can directly reflect the quality of the experience of the bowls baskets of the disinfection cabinets, which is consistent with the subjective experience of users, and verify the effectiveness of the evaluation model.

In the mechanical design of range hoods, grease channel design is a very important design content. Unreasonable design can lead to the accumulation of grease or grease leakage after a period of use, which greatly affects the kitchen hygiene of residents. In most designs, engineers often focus on considering factors such as structural sealing and slope of grease channel, while ignoring the impact of airflow on grease channel. Focuse on the problem of grease accumulation in the design of a certain type of range hood. Using CFD simulation technology for flow field analysis, it was found that the internal airflow characteristics of the range hood caused the accumulation of grease. Based on the analysis results, adjust the oil channel position to avoid areas where airflow rotates, ultimately solving the problem of waste oil accumulation.

The rapid development of generative LLMs, represented by the GPT series, has profoundly changed intelligent interactive products and services. Compared to traditional models, LLMs have new security issues such as hallucination, vulnerability to attacks, and uninterpretability, which significantly hinders their practical applications. Among various application scenarios, smart home has higher requirements for security due to its association with multiple devices and a diverse range of target users. This paper focuses on this scenario, analyzing the three major security issues of content, devices, and privacy that LLMs face in the application of smart homes. Additionally, the targeted solutions are proposed accordingly, which aims to the establishment of the new generation smart home ecosystem that are secure, intelligent, personalized and diversified.

Designed a new type of electric shelf mechanism for refrigerators to improve usability. It has advantages such as high integration and step-less adjustment. The electric shelf's overall design and the driving components' selection and design were analyzed. Simulation and verification formulas were used to determine the basic parameters of the gearbox structure, materials, and gears. Experiments were conducted to verify that the wire rope and zinc head load met actual requirements, with a large safety factor. The key performance indicators of noise and smooth operation were analyzed and optimized to improve the user experience feeling significantly. The above work analyzed the electric shelf mechanism from the aspects of structural design, motor selection, gear verification, material selection, and performance optimization, to improve the research and application of electric shelves for refrigerators.

In response to the problem of excessive bacterial count and pathogenic bacteria in the effluent of commercial water purifiers caused by internal bacterial growth and external environmental interference, focuses on the influence of UV-LED heat dissipation methods, optical performance, and flow channel design, as well as the structural design of radiant illuminance on sterilization performance. Through theoretical analysis and engineering practice, the overall sterilization and antibacterial performance of the machine has been improved. The results show that: by improving the hydraulic cyclone heat dissipation structure, optical performance, and high irradiance flow channel, the effectiveness of UV-LED water flow sterilization can be effectively ensured. By adding independent outlet channels and gap designs, it is possible to effectively prevent external environment from affecting internal water storage. The combination of UV-LED and radiant illuminance helps to ensure the safety of effluent water quality and meets the requirements of the "Sanitary Safety and Functional Evaluation Specification for Drinking Water Quality Treatment Devices - Reverse Osmosis Treatment Devices" standard.

Airflow is an important means of improving thermal comfort in warm and hot environments, but prolonged blowing can also cause various health problems. Compared the changes in joint appearance, tissue structure, and expression of inflammatory cytokines between young and old SD rats in different environments (direct blowing, high humidity, low temperature) by constructing osteoarthritis models. The aim was to evaluate the impact of air conditioning environment on osteoarthritis. Research has found that the appearance of arthritis and inflammatory changes of chondrocytes in rats in high humidity and wind environment were more serious. As for the expression of inflammatory factors, the expressions of IL-1β, TNF-α, VEGF and MMP13 in three experimental groups were all increased, and the increase degree of elderly rats was generally higher than that of young rats. In general, the expression of osteoarthritis inflammatory factors was more sensitive to low temperature environment.

The volume of the compressor directly affects the volume, as well as the installation, safety, and heat dissipation of the outdoor unit of the air conditioner. At present, there are limited methods in the industry to reduce the volume of compressors, especially in aspect of the gas-liquid separator. A miniaturized rotary compressor with a gas-liquid separator installed underneath has been proposed, which reduces the main body width of the compressor by 45% compared to conventional compressors in the same capacity range. By combining simulation and experiment, the heat transfer, gas-liquid separation, and oil return processes inside the gas-liquid separator were analyzed, and the optimal structural design of the gas-liquid separator was confirmed. The results showed that after adopting the innovative "near stagnation refrigerant insulation" technology, the compressor capacity increased by 2.2% and the energy efficiency increased by 3.3%. By reasonable designing of the internal pipe positions, pipe diameters, and oil return holes, the liquid refrigerant amount flush into the cylinder is reduced by 93%, the energy efficiency of the air conditioning system is improved by 0.2% to 3.3%, and the oil level height is guaranteed under various operating conditions. The above research guarantees the small width, high efficiency, and high reliability of the rotary compressors simultaneously, also provides favorable support for the design and development of such kind of compressors.

Based on the literature about human safety current and contact voltage threshold, the difference of human body protection against electric shock under dry condition and wet condition is analyzed. The differences and similarities of the relevant international standards and technical documents of transportable whirlpool SPA are interpreted, and the importance of I_Δn=10 mA PRCD is discussed. On the basis of analyzing the function of protective equipotential bonding, and aiming at its lack of feasibility, it is further demonstrated that the I_Δn=10 mA residual current protection plug with PE wire disconnection can replace the protective equipotential bonding on transportable whirlpool SPA.