Based on the compressor equipped with a 9-groove 6-pole motor, the problem of shaft vibration and noise related to the number of motor poles was studied. Firstly, the composition of radial electromagnetic force with six times frequency was cleared by analyzing the electromagnetic force of motor. Secondly, the vibration characteristics of the rotating shaft was analyzed by simulation and testing analysis, and indicated that the resonance between the six times frequency electromagnetic force and the bending mode of the rotating shaft was the root cause of the vibration and noise of the rotating shaft. Finally, the vibration and noise of the rotating shaft was reduced and the sound quality of the compressor was improved through the simulation analysis and optimization of the bending mode of rotating shaft.

Aiming at the identification of refrigerator fault acoustic signals under compound sound sources, a method for identifying fault acoustic signals of refrigerators based on time-frequency domain clustering analysis is proposed to realize the identification of fault acoustic signals under strong noise. Firstly, the data acquisition instrument is used to obtain the acoustic signals of the refrigerator in the normal operation state and the fault state, and then process them into frames; then the normal n-frame acoustic signals are decomposed by IEEMD, and the full characteristic parameters of each modal component are calculated; then the kmeans++ algorithm is used to analyze the perform clustering analysis on all feature parameters to obtain the optimal features of the expression signal; finally, using the optimal features of n frames as the clustering benchmark, identify the fault signal (including noise), and complete the identification problem of the fault sound signal under strong noise. Acoustic and vibration faults provide pre-processing data support.

Aiming at the problem of wind noise of a refrigerator product, the flow characteristics of its air duct fluid were numerical simulated, and various results are contrastive analyzed. It is concluded that the wind noise is mainly generated by the rotating fan blades and the high-speed air passing through the grid. An optimization scheme is proposed to increase the relative axial position of the fan blade and the grid, and noise reduction is realized by reducing the velocity of air flow through the grid. Then, the fan blade is placed 3.5 mm away from the grid to increase its relative axial position, and the optimized air duct structure is acoustically simulated. It is found that after optimization, the airflow velocity through the grid is reduced, the vortex area formed behind the grid is reduced, and the areas with sound pressure level greater than 20 dB are also significantly smaller. Finally, the noise is reduced by 4.73 dB after optimization according to the calculation of sound pressure level data of each measurement point, which verifies the effectiveness of the proposed optimization proposal.

Electric shelf is a common functional part in high-end refrigerator products, it can realize automatic adjustment of the height of the electric shelf, it is convenient for users to take and place the food materials in refrigerator. However, the planetary gear transmission inside the electric shelf will make noise when working, it will affect the sense of hearing of the user. It aims at the noise problem from the electric shelf in refrigerator, firstly, the cause of noise is identified, focuses on noise reduction optimization of the transmission. Meanwhile, reduces the vibration and noise of the transmission on the delivery path. Finally, the feasibility of the scheme is verified through testing, achieves the purpose of reducing the noise of the electric shelf.

Takes the performance test data of thousands of washing machines tested by the China Household Appliances Testing Institute from 2019 to 2021 as sample, then count and analyze the test data of performance parameters, rinsing performance and wear performance of different types of washing machines. The proportion and changing trend of performance classification in national standards are obtained, and deeply analyze the shortcomings of washing machine industry development and propose improvement directions, at last, provide data support for enterprise research and making analysis.

Hydroxyl radicals (•OH) can be produced by advanced oxidation technology. Applying electrochemical advanced oxidation technology to washing machine, and utilizing the strong oxidation ability of •OH, washing machine may realize the function of dye transfer inhibition, white clothes whitening, bacteria removing and inhibition, improvement of cleaning effect for special stains. Washing and caring effect of washing machine equipped with electrochemical advanced oxidation technology was evaluated comprehensively in this research. The results showed that washing machine equipped with electrochemical advanced oxidation technology can effectively inhibit dye transfer, improve the whiteness of white clothes after washing, achieve sterilizing with low energy consumption, inhibit bacteria in 48 h, improve the cleaning effect of special stains, has no risk getting the color of clothes faded in washing process. In addition, •OH can degrade dyes in washing wastewater, which reveals indispensable environmental values.

Different textile materials and stains have various physical and chemical properties due to their unique composition, structure and arrangement of macro-molecules. Therefore, the attachment and removal methods of different stains on specific textile materials should vary according to the physical and chemical properties. The combination mechanisms between pure cotton, polyester, polyester cotton blended fabrics and silk fabrics with red wine, mud stains and blood stains were analyzed respectively. Under certain washing conditions, the cleaning effects of various stains on different textile fabrics were studied, so as to provide a certain reference for the rational development of subsequent washing procedures of washing machines.

In order to determine the optimal washing parameters of the wave wheel shoe washing machine and improve its washing performance, the wave wheel shoe washing machine was selected as the research object to optimize the washing parameters by selecting key factors that affect washing performance, such as soaking time, washing time, turn-stop ratio, and rinsing time. Through the design of orthogonal experiments and range analysis, the research results show that the significance of various factors on the washing ratio is ranked in descending order: rinsing time>washing time>soaking time>turn-stop ratio. The significance of various factors on wear rate is ranked in descending order: washing time>soaking time>rinsing time>turn-stop ratio. The optimal parameter combination for washing is: washing time 11.5 min, soaking time 6 min, turn-stop ratio 1.5:1.0, and rinsing time 2 min. After parameter optimization, the washing ratio increased by 18% and the wear rate decreased by 22%, significantly improving the washing performance of the shoe washing machine.

Smart home is an important transformation direction for the intelligent household appliance industry. As people increasingly attach importance to new needs such as health, home based medical care, and home based elderly care, smart family health management is receiving increasing attention. However, due to insufficient social awareness of family health management, insufficient personal initiative to participate in health management, and constraints on family and individual health literacy, health management methods do not match family health management needs, which restricts the popularization of family health management. Taking the methodology and theoretical framework of smart family health management as the research object, introducing quality management methods into smart family health management, and using smart appliances and smart homes as health management tools to propose a PDMA cycle methodology for smart family health management, health management implementation theories (human, machine, material, method, environment, etc.), as well as the principles of smart family health management systems, combining data from life with health knowledge, provide a methodological and theoretical framework for smart home health management for the transformation of the household appliance industry.

The booster-driven loop heat pipe system, as an important free cooling system in data centers, can reduce the cooling energy consumption of data centers effectively. The booster is the key component to supply the driving force. Based on the former researches by our group, the leakage gap model of a rolling piston booster was established, and the effects of different leakages and refrigerants were studied and compared. The results indicate that the peak leakages of four leakage gaps for the booster are much lower than that of the compressor, as well as the fluctuation ranges. The variations of the leakages for four refrigerants are the same for both the booster and the compressor. For the axial clearance leakage, the peak leakages of R134a and R22 are much higher than those of R32 and R410A. The leakages are ordered as R134a, R22, R32, R410A from large to small in sequence, which are the opposite for the other three leakage gaps. Among total gap leakages the radial and axial gap leakages are the main leakages.

The comfort of Air conditioning heating has increasingly become the focus of attention of users. Based on the Coanda effect, the structure of air conditioning guide plate is completely designed. The thermal comfort of indoor rooms was verified by experiment, and the PMV index was compared and analyzed. The results show that the thermal comfort of heating can be improved only by improving the structure of air guide plate, and the PMV index at the bottom of the room can be improved by more than 0.05. This effect can be improved even more at the low wind gear, by 0.13.

Combining the poor performance of water spout, the structural characteristics of the water nozzle of a drinking machine is analyzed and the structural characteristics that affect the atomization of water and drift of water are determined; The structure of the original water nozzle is optimized to improve the flow field performance of the water nozzle, which including the porous baffle for buffering incident stream and the gradual shrinkage structure of the front section of the outlet and the diversion structure of the outlet with the method of the steepest descending line theory. Based on the VOF method, the internal gas-liquid distribution and flow field distribution of the optimized water nozzle and the original water nozzle are compared and analyzed. The numerical analysis shows that the flow field of the optimized nozzle has been significantly improved, which can effectively improve the problem of atomization of water and drift of water. The high temperature resistant prototype of the optimized water nozzle is made for testing of the water withdrawal process of the drinking machine. The flow field performance of the optimized water nozzle has been significantly improved in the test.

The rising level of refrigerator preservation technology has met the people's pursuit of dietary safety and health, food taste, texture, nutrition and other factors. A new method is used to improve the quick-freezing effect and thus the quick-freezing preservation of foodstuffs by using a cold storage tray, and the time of spending the zone of maximal crystal forming (ZMCF) is used as a criterion to judge the quick-freezing effect. The experimental results show that ZMCF is reduced by 49.2% compared to conventional storage methods, thus improving the quick-freezing effect. When conducting food testing, as the test package simulates the physical properties of beef, the test package cannot characterise the quick-freeze properties. A food freezing heat transfer model is developed to calculate the cooling time of food products with a minimum deviation of 5% from the experimental cooling time, hoping to provide a useful reference for testing laboratories to avoid multiple experiments and save costs.

In order to study the effect of antibacterial function on HIPS material used in refrigerator liner, two kinds of silver antibacterial agents were used to make antibacterial HIPS liner material. The mechanical properties, oil resistance, antibacterial properties, food safety, machine forming and accelerated aging properties of these materials were studied. The results show that the mechanical properties, physical properties and oil resistance of the two antibacterial HIPS have no obvious changes compared with those of ordinary HIPS. When the amount of antibacterial agent A is 0.5% or the amount of antibacterial agent B is 3%, the antibacterial rate of HIPS liner material against Escherichia coli and Staphylococcus aureus is more than 99.99%, and the food contact test can meet the regulatory requirements. 150 L single-door refrigerator and 520 L multi-door refrigerator were selected for accelerated aging test. The results show that the reliability of the inner parts can still meet the requirements after adding two kinds of antibacterial agents. Silver antibacterial agent can be widely used in refrigerator liner, which can promote the health and safety upgrade of refrigerator industry.

Oven food maturity identification is an important part of intelligent oven. At present, maturity identification in the industry of home appliances is usually achieved by such methods as probes and oxygen sensing, which are marked by their inherent limitation. Spectral imaging, as a kind of optical sensing technology, brings advantages of large amount of information, wide range of detection, and no contact with target. In order to study the application prospects of spectral imaging in oven, the feasibility is demonstrated in principle. After feature extracted through data analysis, machine vision model and classification model of machine learning are built, so that 3 kinds of common food ingredients and 1293 groups of spectral data are collected, analyzed and tested. The results show that spectral imaging could realize positioning of food in oven and accurately identify food maturity, and the cross validation accuracy reaches above 91.3% on average.

Sensory evaluation, specific volume, width-to-height ratio, and texture characteristics are used as evaluation indicators to study the effect of different settings on the edible quality of steamed bread during steam fermentation. Three sets of single factor experiment about temperature rise rate, fermentation temperature and fermentation duration are designed for comparative analysis. The results show that, compared with the original setting of the experimental prototype, when the parameters are adjusted to 400% of the initial temperature rise rate and the fermentation duration is controlled to 80%~100%, the edible quality of steamed bread is better.

Because of the high price of copper, a small tube-diameter evaporator is one of the most efficient technologies to reduce the cost of the dehumidifier. The performance characteristics and cost of dehumidifiers using 7.0 mm/5.0 mm tube diameter evaporators are analyzed based on experiments, and the optimization design methods of 5.0 mm tube diameter evaporators are compared. The results show that under the same test conditions, the overall operating power of dehumidifiers with 7.0 mm/5.0 mm tube evaporators has a negative correlation with the amount of refrigerant. However, the dehumidification capacity and EF (Energy Factor) symbolled as the energy efficiency of the dehumidifier shows a trend of first increasing and then decreasing with the decrease of the refrigerant amount. There is an optimal refrigerant amount. The optimal refrigerant amount of the dehumidifier using a 5.0 mm tube diameter evaporator is at least 4.76% lower than that of the 7.0 mm tube diameter evaporator. The split flow design has the most obvious advantages in improving the dehumidification capacity and EF of the dehumidifier, which can be increased by 11.04% and 10.98% respectively. Under the condition of meeting the design requirements of the same dehumidification capacity and EF, the total cost of a 5.0 mm tube evaporator is 9.66% lower than that of a 7.0 mm tube evaporator.

In order to improve the efficiency of wireless transmission system, it is necessary to make the inverter circuit work in the soft switching state as much as possible and the working frequency as close as possible to the resonant point. Based on the above principle, analyzes the basic conditions for the inverter to enter the soft switching state, and combines the wireless transmission efficiency characteristics of wireless transmission system to obtain a phase-shifting control efficiency optimization method of wireless transmission system. By controlling the working frequency of the inverter circuit, it can work in the maximum inductive reactance point close to the resonant point of the wireless transmission system, so that the circuit can enter the soft switching state more easily under the control mode of phase shift control, so as to reduce the switching loss and improve the working efficiency of the wireless transmission system. The simulation results show that the control method is correct. Finally, a 650W wireless transmission system is used for experimental verification. The simulation and test results can reduce the loss of the wireless transmission system by more than 2 W, indicating that the control method can improve the system efficiency when applied to the wireless transmission system.

In order to reduce the harmonic currents from the outdoor unit of air conditioner and meet the DC voltage demand, single-phase boost power factor correction (PFC) circuit is generally used. With the improvement of power density requirements, the demand for onboard inductance and high carrier frequency PFC technology is increasingly urgent. A high-frequency PFC control scheme without input voltage sensor is proposed. The phase tracking of input voltage is completed by phase-locked loop from input current, and the simulation and practical verification are completed by using double closed-loop control algorithm. Compared with the traditional scheme, which omits input voltage detection, the circuit is more optimized and the algorithm is simpler. Finally, it is applied to 3 P cabinet air conditioner, the power factor can reach more than 0.99 under rated operation, the harmonic current meets the IEC standards, and the reliability test meets the actual requirements.

The washing machine has the function of automatic lifting castor movement, which is of great significance for cleaning the bottom of the washing machine conveniently, moving the washing machine safely and conveniently, elderly-oriented. Based on the goal of providing users with a simple, convenient, durable and reliable washing machine moving solution, an automatic lifting castor mobile device has been developed. The device has designed a set of casters for mobile washing machines. Through precise calculation of the running track of the casters, theoretical calculation of motor torque, simulation, a large number of reliability tests and user experience, it has innovatively designed a washing machine with motor gear variable speed transmission, inching control in place, lever drive lifting, universal wheel movement, which can easily move the washing machine through automatic lifting casters, it has solved the industrial problem of heavy machinery and difficult handling in the drum washing machine industry, and improved the aging of washing machine products.

Present a new type of integral kitchen air conditioner. According to the characteristics of heavy oil smoke in the kitchen environment, four types of air filters, including HEPA filter, nickel foam filter, porous activated carbon filter and stainless steel filter, were designed. The filtration effect of the four prototypes and the refrigeration performance before and after 300 cycles of long-term operation of cooking were tested. The results show that: the HEPA filter is the best for oil fume filtration, but the air resistance of the filter is large. The air volume decreases 14 m³/h, and the rated refrigeration capacity decreases 81 W after a long-term operation, the air volume and the refrigeration capacity decreases greatly. The stainless steel filter has the smallest wind resistance, but it’s the worst for oil fume filtration. After a long-term operation, the air volume decreases by 10 m³/h, the rated refrigeration capacity decreases by 166 W, and it is most obviously, the main reason is that the oil fume leaks and attaches to the aluminum fin of the evaporator, which affects the heat exchange efficiency of the evaporator. The activated carbon filter is good for fume filtration, and its wind resistance is small. After long-term operation, the air volume and rated refrigeration capacity decreases by 5 m³/h and 49 W, it’s not significant. The porous structure of the nickel foam filter can filter the oil fume effectively, and its wind resistance is small too. After a long-term operation, the air volume and rated cooling capacity decreases by 3 m³/h and 34 W respectively, the attenuation of air volume and refrigeration capacity is the smallest. The nickel foam filter can be used sustainably after cleaning, which is an ideal choice for kitchen air-conditioner filter.

The accelerated development of society and the improvement of consumption level can promote the market development to a certain extent. Home appliance enterprises should improve the user experience in a more comprehensive way, and make the user-oriented instead of the development ability-oriented, so that the closed-loop experience research can be formed within the home appliance enterprises, and the closed-loop experience can be formed when users experience home appliances, so as to build a complete whole-process user experience and establish a good user experience research system. Based on desktop research, literature review and many years' research experience, outputs the research on user experience of household appliances with contact orientation. The whole process is divided into the whole life cycle of products and the whole process of product experience. From the perspective of enterprises and users, the whole process of user perspective is divided into pre-contact, first contact, core contact and final contact, so as to improve the user research process in the industry, realize the closed-loop experience, better convey the brand value of enterprises and effectively enhance the brand user experience and brand.