By comparing the contents and index changes of the old and new national standards for range hoods, the main upgrading contents and technical requirements of the new national standards are listed, and the promoting effect of the new national standards on the industry development of range hoods is expounded. Combined with new and old standards, analyzes some performance parameters of core products of existing mainstream manufacturers, and points out the status quo and differences of performance parameters. In view of the new national standard regulations to be implemented soon, analyzes the working air volume, working noise and working power of existing products, points out the problems caused by product competition in the current market, and puts forward some technical directions for future product research.

Cleaning capability is an important research direction of dishwasher. Fan nozzles are widely used in cleaning industry because of its large coverage and uniform injection, so it is proposed to apply fan nozzles in dishwasher scenarios. The jet model of fan-shaped nozzle is established by computational fluid dynamics (CFD), the numerical simulation results are analyzed, and the jet characteristics of the fan-shaped nozzle are obtained. The advantages and disadvantages of the circular nozzle and the fan-shaped nozzle jet characteristics are compared and analyzed. High-speed photography technology was used to photograph the actual jet flow of two nozzles. Finally, by analyzing and comparing the cleaning test data, it was found that the cleaning index of the fan-shaped nozzle spray arm can reach 1.2, which is 1.11 higher than that of the circular nozzle. Further verify the improvement effect of the fan-shaped nozzle on the cleaning efficiency of the dishwasher, and provide direction for the optimization of the dishwasher spray arm.

For the dishwasher's nearly square washing area, the circular coverage formed by common sprays can cause the problem of insufficient washing at the four corners. Based on the study of planetary gear train mechanisms, determines a primary transmission planetary gear train mechanism as the basic model and further construct different sprays with addition of intermediate transmission gear, crank slider mechanism, or crank rocker mechanism. Through motion analysis, the specific tracks of spray orifices are obtained, achieving supplementary coverage of the four corner areas. After deeply analysis and comparison, a dishwasher spray with the rocker satellite sprays was finally proposed which not only can form a nearly square coverage effect, but also enhances the washing coverage of the square peripheral area through the tracks. Through experiments the improvement of dishwasher cleaning performance has been effectively verified.

Selected eggplant to explore the effect of steam quantity (0 g/min, 1.8 g/min, 5.0 g/min and 10.5 g/min) on the quality of roasted eggplant by analyzing its sensory quality, texture and polyphenol content. In addition, the best steam assisted roasting technology was compared with the existing roasting technology. The results showed that the addition of steam had a significant impact on the quality of roasted eggplant. With the increase of the amount of steam, the sensory evaluation score of roasted eggplant was gradually improved, hardness and rupture strength were significantly reduced, and polyphenol content was significantly increased. The hardness and rupture strength of roasted eggplant at 10.5 g/min were the lowest, and its sensory was the best. The polyphenol content of roasted eggplant at 10.5 g/min was the highest (131.79 mg/100 g), which was 44.44% higher than non-steam group (0 g/min). The polyphenol content of eggplant roasted by the best steam assisted roasting process was 12.67% higher than that of the existing process. The addition of steam provides consumers with a more convenient and nutritious way to roast eggplant in the steam oven.

In order to determine the feasibility and advantages of using superheated steam in steam ovens, a study was conducted on the differences in cooking effects between it and the ordinary baking mode. The pure baking mode of the steam oven adds superheated steam, called degreasing baking mode. The experimental results showed that under the same cooking temperature and time, the fat content of pork pancakes roasted in the defatted roasting mode decreased by 9.32%, the salt reduction rate increased by 13.26%, and the generation of heterocyclic amines decreased by about 37.5% compared to the pure roasting mode; The content of peroxide value in lard obtained by roasting pig fat in the defatted roasting mode decreased by 72.86% compared to the pure roasting mode; Compared to the pure roasting mode, the defatted roasting mode improved the tenderness of fish meat and increased its water retention rate by 13.76%; The retention rate of vitamin C in roasted broccoli under degreasing roasting mode increased by 3.86% compared to pure roasting mode; The defatted roasting mode retains more flavor compounds in roasted carrots compared to the pure roasting mode. Based on a comprehensive analysis of the above data, it can be concluded that the application of superheated steam technology on the steam grill has advantages in defatting, reducing salt, antioxidant, and enhancing taste in cooking.

For air fryers heated by high-speed forced convection circulation, there is an uneven temperature field in the inner chamber, which leads to the need to flip the surface during cooking. Based on the method of computational fluid dynamics, the three-dimensional numerical simulation analysis of the temperature field and velocity flow field of the air fryer was carried out by using Fluent software. Further, the accuracy of the numerical simulation method was verified by comparing the measured temperature data with the simulation data. By changing the motor speed, baking plate, and barrel structure of the air fryer, numerical simulation research was conducted, and the experimental verification and comparative analysis show that the motor speed is increased, the opening of the baking tray is improved, and the structure of the baking tray is changed to a separate type, so that the overall three-dimensional temperature difference of the inner cavity of the air fryer decreases by about 11℃, and the temperature uniformity of the inner cavity is improved.

Roll-type reverse osmosis membrane filter core is widely used in water purification because of its large filling area and high separation efficiency. With the implementation of GB 34914 water efficiency standards, the performance of reverse osmosis (ro) membrane filter has met great challenges due to the increase of concentration ratio and operation load under high water efficiency conditions. By analyzing the filtration mechanism, fouling mechanism and mass transfer process equation, it is concluded that the structure of filter element has an important influence on the mass transfer process of reverse osmosis membrane filtration, and then affects the performance of filter element. In order to improve the performance of reverse osmosis membrane, the law of filter performance was studied from four aspects: the direction of water inlet and outlet of filter channel, the design of membrane bag pages, the selection of inlet screen, and the selection of fresh screen, it provides the design idea and technical scheme for improving the performance of reverse osmosis membrane filter core.

Studied and analyzed the basic mechanism of vibration and noise generation of single cylinder compressors above rated frequency. Based on mechanism analysis and theoretical derivation, the current harmonic suppression technology in the field of servo electronic control is introduced into the automatic compensation scheme for vibration harmonics of single cylinder compressors operating at frequencies higher than the rated frequency. Based on the actual load characteristics and driving system characteristics of the compressor, a thorough analysis of the vibration harmonic suppression method system function and control block diagram is conducted, and a specific design method for optimizing control parameters is further provided. Finally, using Simulink software, a model of the automatic compensation scheme for current harmonics above the rated frequency of a single cylinder compressor was designed. The effectiveness of the automatic compensation scheme for current harmonics above the rated frequency of a single cylinder compressor was verified, in simulation, the FFT result of third harmonic decline from 36.8 dB to 11.5 dB, comparison of simulation results and experimental test data; And experimental verification was conducted to clarify the effectiveness of the algorithm.

As the overall volume of the air conditioner or the volume requirements of the compressor compartment continue to decrease, more compact requirements have been put forward for the size of the compressor. The reduction in internal space poses a quality risk of scratches between the rotor and stator leads. Establishes a rotor end ring resistance network model and analyzes that the current is mainly concentrated in the lower layer of the end ring. The continuous increase in the height of the end ring brings about efficiency improvement and reduced benefits. Through the analysis of eddy currents induced by stator leakage magnetic field, it is concluded that increasing the height of the end ring carries the risk of loss increase and efficiency decrease. The correctness of the analysis is verified through three-dimensional finite element simulation. The experimental verification shows that after the height of the end ring decreases, the energy efficiency of the motor and compressor does not decrease, and the safety gap between the rotor and stator leads increases. This provides technical measures to improve the quality risk of miniaturized compressors without reducing energy efficiency.

One of the limiting factors of the refrigerating capacity range of household air conditioners under high temperatures is the life of the electrolytic capacitor on the driving board of the outdoor unit. At present, the service life of the electrolytic capacitor is generally guaranteed by limiting the operating frequency of the compressor, which causes a waste of the cooling capacity of the air conditioner. By evaluating the influencing factors of electrolytic capacitor life, the relationship between surface temperature, self temperature rise and life of electrolytic capacitor is analyzed. Without changing or adding hardware sensors, the methods of electrolytic capacitor ripple voltage estimating temperature rise and linear fitting estimating surface temperature are proposed to estimate the life of electrolytic capacitor in real time, and then dynamically adjust the operating frequency of compressor under high temperature. Realize the adjustment of compressor operating frequency based on user usage, and for most users, can increase the air conditioning cooling capacity by more than 5% under high temperature.

Based on big data analysis, analyzes the problems of excess capacity and low efficiency in low-load household multi-line operation. By optimizing the volume ratio, pump structure, switching mechanism and other aspects of variable-volume compressor, optimizes the motor groove pole matching and winding mode, and combines winding switching technology, inverter electric control optimization and other technologies. Reduce the friction power consumption, leakage loss, exhaust resistance of the compressor, improve the low frequency efficiency of the motor, reduce the frequency converter control loss, thus expanding the minimum cold output, greatly improve the low frequency energy efficiency of the compressor, applied to the home multi-line system can make the low load energy efficiency increased by 20%.

In order to achieve simulation and prediction of the vibration performance of motor supports, proposed an analysis method based on the combination of load extraction and finite element simulation. Firstly, the dynamic load identification of the motor is carried out based on the matrix inversion method. Then establish a finite element model, use the extracted motor load as an excitation for harmonic response simulation analysis, and obtain the frequency response curve of the target point. Finally, a comparison was conducted between experiments and simulations to compare the fitting degree of the corresponding frequency domain curves and the trend of RMS values within the 10~150 Hz frequency zone. The results show that the test results of the load extraction experiment have a high degree of agreement with the fitting results, and the load accuracy is relatively high. The deviation between the natural frequency of the established simulation model and the natural frequency of the modal test is within 5%, and the MAC value of the vibration mode comparison is above 95%, indicating high model accuracy. The consistency between the working condition data and the frequency response curve is high, and the minimum error between the experimental RMS value and the simulated RMS value is only 5.82%, achieving simulation prediction of the vibration performance of the motor support.

The door self-locking part of refrigerator is the important component connecting the refrigerator cabinet and the door, it mainly includes hinge and suction assisting device, the self-locking part makes the door have a certain pre-tightening force after it is closed. The unreasonable design will lead to a poor experience of opening and closing the door, the door cannot be closed tightly, noise generated when opening and closing the door and so on. In view of the problem that the door self-locking part of a certain refrigerator in our company generates much noise during the door closing, analyzes the kinematics and dynamic behaviors of the original suction assisting device in the process of door closing with the help of simulation software, optimizes the structure repeatedly, analyzes the feasibility of the scheme adopts simulation means. Finally, makes the samples and verifies their practical noise reduction and self-locking force effects. It is found that the optimized suction assisting device can greatly reduce the noise during the door closing under the premise of ensuring the original preload, more than 30% reduction in the maximum sound pressure level, and provides users with good auditory perception experiences.

Based on the SWOT-AHP model, analyze the development strategy of the traditional Chinese medicine household appliance industry in Foshan City. Internal advantages, internal disadvantages, external opportunities, and external challenges are used as the criteria layer, and 14 factors are identified as the indicator layer. The importance of each factor is quantified and weighted, and a strategic quadrilateral is drawn to determine the overall direction of the strategy. The results indicate that the advantages and opportunities for the development of traditional Chinese medicine household appliance industry in Foshan are stronger than the disadvantages and challenges, and the strategic choice should be based on the SO strategy. Suggestion: Take the development of the "health industry" as an important direction for the development planning of the home appliance industry, and encourage the development of the traditional Chinese medicine household appliance industry; Leading household appliance enterprises should take the lead and make full use of existing theories and technologies to implement the transformation of achievements; Establish a basic research institution for traditional Chinese medicine household appliances in Foshan, and establish a demand release mechanism for traditional Chinese medicine household appliance enterprises; Implement policies to promote the consumption of traditional Chinese medicine household appliance products and improve the level of full chain services; Innovation management mechanism and system, and cooperate with multiple departments.

Following the color harmonization theory and combining the NCD perceptual color system to provide a more scientific evaluation method for the color matching design of the product will more effectively enhance the aesthetic of the product. The application and analysis of product color matching based on the Moon & Spencer color harmony principle and the Birkhoff aesthetic evaluation model method combine to the NCD color psychological feelings. In harmonic theory, different intervals and harmonic relationships of hue, value, and chroma will have different effects on aesthetic values. But in perceptual research, regardless of the aesthetic value, the color scheme has a different style impression. Under the harmonization theory, most of the existing color matching aesthetic values of products are greater than 0.5. The most optimal harmonic effect brought by hue difference is same color harmony area. The worst one is second ambiguous area. The best effect of brightness chroma difference is the contrast and harmonization area, the worst is the same tone area, in the product color matching to improve the contrast of two colors gloss will increase its aesthetic value. At the same time, the perceptual color system NCD is used to combine psychological feelings to summarize the style of product color and derive its color scheme. The above methods provide the necessary theoretical basis and evaluation for the future color matching of appliances, so as to improve the aesthetic and harmony of product color matching.

Washing machine products have become one of the indispensable electrical appliances in households. The rinsing effect is an important indicator that users will pay attention to when choosing washing machine products. Taking a fully automatic drum washing machine as an example, the evaluation method of relative uncertainty is used to analyze the uncertainty of rinsing effect testing. Through analysis, it is found that the repeatability of the measurement process and environmental temperature and humidity have the most significant impact on the measurement results. This provides a reference for enterprises to improve the performance of washing machines, improve the quality of washing machine products, and improve the accuracy of washing machine performance testing for third-party testing institutions.

According to the requirements of the equipment power supply scheme in the DC power system, analyzes and compares the characteristics of typical power supply topologies, chooses the dual-transistor forward topology, and sorts out the key device parameter design methods and selection calculations in detail according to the application requirements. Focusing on the control loop analysis and modeling for power supply stability, a small-signal simulation model of the control system is built, and the control loop parameter design and stability are analyzed through simulation analysis. And a 200 W power level prototype is developed. The performance indicators of the prototype meet the design requirements, the control performance is stable, demonstrating the correctness and effectiveness of the theoretical analysis.

In recent years, smart home systems have achieved rapid development. Single live wire power supply system is an important part of it. However, traditional offline power supply circuit is difficult to adapt to its working environment. New structures are in dire need of development. Aiming at the characteristics of extremely low working current of single live wire power supply system, the traditional structure of RCC switching mode circuit is modified to reduce its working current. The working current is significantly reduced. After circuit simulation, a actual product is produced and the measured working current is only 0.8 mA in test, which is more than 50% lower than that in traditional structure. It is proved to have high practical value with simple structure, stable performance, and low cost.

Electrical products need to undergo transportation before being put into use, and vibration during transportation can have a certain impact on the life and reliability of the products. It is necessary to test the resistance to transport vibration of electrical products by means of simulated transport vibration test. Based on relevant standards for transportation vibration, experimental guidelines for conducting simulated transportation vibration tests are provided, and key points related to sample installation, composition of transportation vibration tests, and selection of acceleration density spectra are summarized. Comparative analysis was conducted on the severity of acceleration density spectrum vibration levels in common transportation vibration standards such as GB/T 2423, GB/T 4857, ISTA 3A, ASTM D4169-16, GJB 150, etc. Suggestions were given on how to choose appropriate transportation vibration standards, in order to better conduct simulated road transportation vibration tests for products that need to be transported. The analysis results show that the military standard transportation vibration test level is higher than the civilian standard, and the recommended transportation vibration test level for the civilian GB/T 2423 series standard is also larger; most products can be tested using the GB/T 4857.23 highway general vibration standard spectrum during transportation vibration testing.

Computational fluid dynamics (CFD) simulation is an important method for optimization and research of multi blade centrifugal fan. The details of geometric processing in the rotation domain of the fan, mesh types, etc. will have a certain impact on the CFD simulation results. Firstly, divide the same impeller into different meshes, and calculate the impact of different mesh conditions on the CFD calculation results. The mesh conditions mainly include different mesh types: hexahedral, hybrid, mesh with and without boundary layer, and whether the rotation domain is expanded. Then, a case was presented to analyze the error in simulation results. The results show that, the non-refined boundary layer mesh and the expansion of the rotation domain will lead to the deviation of the simulation results. After the multi blade centrifugal fan model in this research case is modified, the maximum difference between the simulation results and the measured results is reduced from 4.40% to 0.73%. The research is of great significance to improve the accuracy of multi blade centrifugal fan simulation.