The door double-axis self-locking part of refrigerator has no fixed rotation axis, it makes the door body will not interfere with the objects on the side of the refrigerator during the door opening and closing. Similar to single-axis self-locking part, the unreasonable design will lead to a poor force sense during the door opening and closing, or the door cannot be closed tightly and so on. It aims at the problem that the door double-axis self-locking part of a high-end refrigerator has excessive pushing force and a poor smoothness of force sense during the door closing process, analyzes the original self-locking force with the help of simulation means, optimizes the structures of hinge and suction assisting device, analyzes the feasibility of the scheme adopts simulation means, at last makes the samples and verifies their practical effects. The results show that the optimized double-axis self-locking part can greatly reduce the pushing force during the door closing process on the premise of ensuring the self-locking function, at the same time it improves the smoothness of force sense, and provides the control and optimization directions for the design of double-axis self-locking part.

According to the three structural parameters of the baffle inside the centrifugal fan, including the horizontal Angle θ, the length L and the through-hole diameter D, the response surface method was used to design different parameter combination schemes, and two groups of optimization schemes were obtained. RNG k-ε turbulence model is used to simulate the internal flow of centrifugal fan. The test method is used to verify the uniformity and noise performance of centrifugal fan. The results show that the influence of Angle θ on the uniformity of air discharge is the most significant. In optimization scheme 1, the air outlet uniformity and aerodynamic noise performance are the best. At this time, θ=33.06°, L=43.33 mm, D=4.67 mm, and the standard deviation σ of wind speed value at each measuring point of outlet decreases from 1.42 to 0.65, with a decrease of 54%. The measured noise value is reduced from 43.6 dB(A) to 40.2 dB(A), with a decrease of 7.8%. Therefore, optimizing the structural parameters of the baffle can effectively improve the internal flow state of the centrifugal fan, improve the uniformity of the outlet air and aerodynamic noise performance of the centrifugal fan.

At present, most of the high-end thin-wall refrigerators launched on the market use vacuum insulation panels to reduce the foam layer thickness of the box and door body to achieve the purpose of reducing product power consumption and improving product volume ratio. However, the vacuum insulation board is expensive and easily damaged, and a large number of protective measures are required during the manufacture of the refrigerator. In order to achieve easy manufacturing, lower cost and improve product competitiveness, the research aims to achieve the original performance without changing the foam layer thickness of the box after removing the vacuum insulation board. After the vacuum insulation board is cancelled, the cooling leakage of the box is bound to increase, and problems such as not being able to achieve level 1 energy efficiency, non-standard high-ring temperature storage temperature, and unqualified condensation occur. The method of theoretical analysis and practical test is used to improve the cooling efficiency, reduce the standby power consumption, and reduce the leakage of the box door seal. The test results show that the power consumption of the whole machine increases by about 8% after the vacuum insulation board is canceled, and the power consumption of the whole machine decreases by about 8% after the optimization design, and the goal of level 1 energy efficiency is achieved. The storage temperature and condensation test were improved from unqualified to qualified, and finally achieved various performance and reliability indicators. The research scheme provides an optimization idea for the vacuum insulation board of the box, and can also be used as a reference when the performance of the product is improved.

Air fryers have been widely loved in recent years due to their advantages of simple operation, safety, economy, and hygiene. The principle is to use high-temperature air to heat food in a closed frying pan at high speed, but users use disposable oil paper to avoid cleaning, which affects the uniformity of the flow field and causes users to flip the surface midway during the cooking process. Improving the problem of flipping during cooking by adding a heat source to the bottom of the chamber of an air fryer, and appling Fluent software to conduct three-dimensional numerical simulation of the temperature at the bottom of the chamber of the air fryer. The temperature distribution at the bottom of the chamber is obtained, and the reasons for the uneven temperature distribution at the bottom of the chamber when the heating tube is uniformly wound are analyzed. This provides guidance for improving the design of the structure of the heating tube. Through CFD simulation improvement and cooking effect verification, it is found that adding a lower heating pipe is beneficial for improving the bottom heating capacity, thereby achieving a mid way flip free effect.

According to the high-speed fan impeller has cracking failure cases at the client, and it is confirmed through research that the failure is caused by improper dynamic balance weight removal strategy of the impeller. At present, most researches only discuss how to realize automatic dynamic balancing, and there is less research on the influence of different dynamic balancing weight-loss strategies on the impeller structure, so it is particularly important to study the dynamic balancing weight-loss strategies of the impeller. The analysis method of finite element simulation is used to discuss the advantages and disadvantages of different weight removal strategies for impeller dynamic balance from four factors, and an ideal dynamic balance weight removal strategy and optimization method for high-speed fan impeller are proposed. The relative accuracy of the theoretical model is verified through the comparison of simulation and experimental test data. Finally, according to the theoretical basis, the corresponding equipment is made to carry out impeller dynamic balancing and weight removal, further verifying its feasibility and effectiveness, and providing theoretical basis and application reference for the improvement and control of impeller dynamic balancing process of high-speed fan rotor system.

In view of the cracking phenomenon of refrigerator drawer in the process of high and low temperature testing with oil, takes the injection drawer of biomass filler composite material developed by our company as an example to explore the causes of cracking through material stress simulation analysis and CAE mold flow analysis. The results show that the main cause of drawer cracking is the inconsistent cooling rate of vertical support bars in the drawer and the surrounding area. The cooling part first forms the support structure, and the cooling slow part is constrained by the support structure during the cooling contraction, resulting in stress concentration cracking. The material stress simulation analysis results and CAE model flow analysis show that the stress concentration of the drawer can be effectively reduced after removing the vertical support ribs on the side of the drawer, so as to avoid the occurrence of cracks in the high and low temperature test of oiling.

Taking the suspension system of a specific type of drum washer as an example. Firstly, the strength of a drum washer is calculated under fixed restraint conditions by multi-body dynamics and linear static analysis methods, respectively, and the calculation results are compared and analyzed. Secondly, based on multi-body dynamics, the influence of gravity on the strength calculation results of the tub is analyzed. Finally, the strength of the tub, shaft, housing bearing, and flange shaft is checked by the complete model of a drum washer. The results show that the maximum displacement and the maximum stress difference of the tub increase with the rotational speed of the rotating parts were obtained through linear static and multi-body dynamics analysis. The consideration of gravity increases the maximum displacement of the tub by 2.70% and the maximum stress by 1.59%. The safety factors of the tub, shaft, housing bearing, and flange shaft are above 2.5 by checking the complete model of a drum washer. By calculation, the rating life of the front/rear bearings of a drum washer is 633 h and 768 h.

In the simulation transportation sweep frequency vibration experiment of a household air conditioning outdoor unit project in the development stage, the phenomenon of tube breaking occurred at the root of the liquid outlet pipe of the electronic expansion valve. Through finite element simulation analysis, it was found that the electronic expansion valve assembly in the original scheme had an overall up and down mode at the frequency of 77 Hz, which was the main cause of tube breaking. In order to solve this problem, an optimization scheme to strengthen the welding position of the pipe is proposed. The simulation results show that no overall up and down modes appear within the experimental frequency range after optimization, and the stress at the original broken pipe position is reduced by 73.1% compared with the original pipe scheme. The experimental results show that the reinforced pipe optimization scheme is effective and can avoid the problem of broken pipe of the electronic expansion valve outlet pipe of this model.

When the air conditioner fan starts, it may be in a rotating state due to the external wind, which is called flying start. Accurate initial position and speed detection are the basis for flying start. Firstly, the principle of zero-voltage vector pulse method is analyzed, and then the current of PMSM under the action of zero-voltage vector pulse is solved, and then the initial position and speed detection method of PMSM based on zero-voltage vector pulse method is given. On this basis, the determination method of pulse width and interval is designed, and finally experimental verification is carried out. The experimental results show that the zero-voltage vector pulse method can effectively observe the initial position and speed of the air conditioning fan under rotating state, and realize the start of the vehicle.

The air flow organization form and effect of air conditioning are important factors that affect human thermal comfort, and have always been the hotspots and difficulties in the field. In order to explore the air distribution effect of the split hanging air conditioner with cross flow fan under the refrigeration condition and optimize it, used Computational Fluid Dynamics (CFD) technology to carry out a full-scale simulation of the air distribution form of a split hanging air conditioner, studied the distribution of indoor velocity field and temperature field under different air volume conditions, and compared the numerical simulation results with the experimental results. The research results are as follows: the error between the simulation results of indoor temperature distribution and the test results is controlled within 10%, and the temperature error of 76.2% of the measuring points is within 5%. Has a good reference value for the development and optimization of new models, and the full scale simulation method used has a good prediction effect on the indoor air distribution effect of air conditioning.

The widespread use of multi-connectors in the home improvement market has put forward higher requirements on the size of indoor unit heat exchangers. The heat exchanger copper tube and fin specifications, installation angle, etc. have a significant impact on the heat transfer capacity of indoor units. The wind field distribution of different heat exchanger angles was firstly studied by CFD simulation software for an indoor unit heat exchanger, and then the wind resistance and heat transfer capacity of heat exchanger with Φ7 mm and Φ5 mm tube diameters were studied experimentally. CFD simulation research has found that the V-shaped 54° wind field distribution is optimal in a limited space. The experimental results indicate that the V-shaped 54 ° cooling and heating capacity is the best in a limited space. Considering that the increase in the width of the unit has a certain impact on the transportation of the unit, the actual angle of the heat exchanger should be within the range of 51°~57°.

PFC (Power Factor Correction) circuit plays an important role in harmonic current suppression and improving power factor for air conditioner. With the development trend of high-frequency and miniaturization of air conditioner driver, the carrier frequency of PFC circuits is constantly increasing, and currently has reached the range of 60 kHz. The issue of conducted interference caused by high-frequency switching in PFC circuits is becoming increasingly prominent. Aiming at the issue, an interference suppression method is proposed. The differential mode interference and Common-mode interference in conducted interference are respectively processed by near-field coupling suppression and high-frequency noise absorption. Based on the above methods, the amplitude of interference has been reduced. The method is proved by experiments on 3 HP air conditioner. Through these experiments, it can be seen that before the EMI improvement the average value of the highest point in the PFC conducted interference test curve has a relative margin of 0 dB to the national standard, and after adding the improvement method, the margin value is 11 dB. The test results comply with national standards, verifying the effectiveness of the method. Also, the method has low cost advantage and is suitable for mass application in air conditioner products.

In order to study the energy separation of vortex tube with four flow path nozzles, energy separation was experimentally studied in vortex tube with compressed air as the working medium. Experimental research results showed that vortex tube with four flow path nozzles can get best cold and hot temperature effect at 0.35 and 0.8 cold mass flow fraction. With the rise of inlet pressure from 0.35 MPa to 0.5 MPa, the best cooling effects increase from 23.1 K to 29.1 K, but the best cooling effects mass flow fraction decrease from 0.38 to 0.32, and the best heating effects increase from 41.3 K to 50.8 K, but the best heating effects mass flow fraction decrease from 0.82 to 0.77.

Two color measurement methods, NCS (Natural Color System) color card and color difference meter, were used to collect color difference data of broccoli steamed by 0.20, 0.45, and 0.80 g/(min·L) steam. The obtained color difference data were processed to obtain Yellowness difference (ΔG) of the NCS color card, yellowness value of the color difference meter (b value), yellowness difference of the color difference meter (Δb value), and total difference of the color difference meter (ΔE value) and other indicators. Finally, through comparative analysis ΔE, the highest probability of correctly distinguishing the three kinds of steam is 87.5%, and the coefficient of variation is the lowest, which is more suitable as an evaluation index. It was also found that with the increase of ΔE, the amount of steam decreased gradually, the cooking time of broccoli increased gradually, and the vitamin content decreased gradually.

Comparison with air cleaner, household fresh-air cleaner can further exhaust the accumulated CO₂ as well as formaldehyde, TVOC and other chemical pollutants in the room, and fresh-air cleaner with heat exchanger can also reduce heat/cooling losses, becoming an emerging air cleaning product. The test chamber was built to simulate the actual working state of fresh-air cleaner, and about 30 fresh-air cleaner models of different types were selected for multiple tests, and the same fresh-air cleaner of about 10 models was tested repeatedly. The deviation of repeated tests was less than 3%, and the feasibility of the method was proved by verifying the consistency of the purification effect. The above results indicate that the test simulation chamber and the measurement method of purification performance adopted can be used to evaluate the related performance of household fresh-air cleaner.

Compressor is the core component of refrigeration equipment and the main source of equipment noise. The abnormal detection of product quality based on big data is a typical demand of industrial intelligence. It is based on industrial data and artificial intelligence methods, and realizes the abnormal detection of products by establishing data-driven models. High quality labeled samples are the key to compressor anomaly detection using artificial intelligence methods. An autoencoder-based automatic sample labeling method is proposed. Based on the sample reconstruction error sequence of the autoencoder, the samples are gradually adjusted, and the training samples are gradually extracted. Finally, normal samples and fault samples with accurate labeling are extracted from a large number of samples with labeling errors. This method solves the problem of real-time labeling of large-scale samples manually, and can provide accurate labeling training samples for online anomaly detection of products.

The measurement accuracy requirement of the national standard for the ambient humidity meter for energy efficiency testing of storage type electric water heaters is ±1%RH, which differs greatly from the requirements of similar foreign standards, and the higher accuracy requires the higher cost of configuring measuring instruments, and the requirements for the use process are relatively strict and expensive. Analyzed the environmental humidity requirements for energy efficiency testing of storage type electric water heaters and pointed out that the influence of environmental humidity on the energy efficiency measurement results can be ignored, and through the analysis of the measurement range and measurement accuracy requirements, combined with the applicable requirements of the CTL resolution, it is determined that an accuracy of ±6%RH can meet the requirements for use, so the accuracy of ±1%RH stipulated in GB 21519—2008 and GB/T 20289—2006 can meet the requirements for use. The requirement that the accuracy is ±1%RH is an obviously unreasonable problem.

The traditional design method in home appliance industry is more and more difficult to meet the needs of the rapid development of home appliance industry due to its limitations, such as high test cost, long test cycle, less test conditions, and unable to filter invalid design methods. The introduction of simulation technology in the process of product development providing a new design methods for major home appliance enterprises, explored by major home appliance enterprises. A packaged dishwasher is taken as the background. Firstly, the mechanical properties of the key components of the dishwasher are tested, and the constitutive model of material in the simulation is benchmarked by using Radioss; Secondly, according to the design drawings provided by the design department, the finite element model of dishwasher is established by HyperMesh; Thirdly, by way of the dropping simulation of dishwasher with package, failure analysis on the fracture of sump are found, and the effective quality improvement schemes are found too through multiple simulation iterations; Finally, the validity of the simulation results is verified by the physical test of dropping. The results show that, in the process of product development of dishwasher, after the introduction of dropping simulation technology, most of the physical tests can be replaced, the anti-dropping capability of products can be quickly evaluated and improved.

The existing heat pump dryer has a problem of high operational noise, mainly due to the excessive aerodynamic noise of the centrifugal fan. As a household appliance, the operational noise directly affects user experience. The flow characteristics of the original fan duct system were analyzed using Computational Fluid Dynamics (CFD) simulation technology to identify the reasons for the high operational noise. Based on the CFD analysis, an optimized fan duct design was proposed, which included targeted optimizations of the volute structure and a completely redesigned centrifugal fan. Experimental data from prototype testing showed that, under the same airflow rate, the new design reduced the fan operating speed by 38.3% and decreased the noise level by 2.91 dB(A). The optimization analysis results provide guidance for the design of heat pump dryer fans and also have implications for the design and optimization of related household appliances.

In order to explore the fresh-keeping effect of natural slow-release agents on typical cooked food under the refrigerator conditions, the indexes of N-nitrosamine, nitrite, biogenic amine, total bacterial count in the sauce beef and lunch meat stored in the refrigerator freezer were determined. The results showed that after 12 days of storage at 4℃, total bacterial count in the sauce beef and Lunch meat samples with slow-release agents was 20.0% and 15.79% lower than that in the control group, respectively. Because microorganisms can participate in the chemical reaction of nitrosation, the reduction of total bacterial count reduces the accumulation of biogenic amine under the storage condition of 4℃, and inhibits the production of N-nitrosamine during the storage of sauce beef and lunch meat. It is inferred from the nitrite content that the slow-release agent inhibits the reaction pathway of nitrite conversion to N-nitrosamine.

The sale of web marketing is one of the most important distribution channels. Due to the large volume and quality of the built-in microwave oven, as well as complexity and uncertainty of its transportation environment, the falling damage can regularly takes place. To the deformation of the microwave closure in package impact test, analysis the cause of falling damage, construct the mechanics model about damage, according to mechanical principle. Foam anti-vibration cushion liner is optimized, to achieve the purpose, which can obtain a more reasonable moment distribution and decrease the maximum bending moment value. After optimization, the maximum bending stress of the closure reduces to 50% of the original position. The failure problems of the closure deformation are solved through experimental verification. The above mentioned mechanics model plays an important theoretical guiding role in package design of large home appliance.