Fan Cover Research Articles

The Fan Design Optimization for Totally Enclosed Type Induction Motor with Experimentally Verified CFD-Based MOGA Simulations

The energy efficient electric motors save energy thus reduce operating costs. Since there are several losses affecting the motor efficiency, fan design plays an important role to minimize these losses. This study examines the effects of the design parameters of a radial bladed fan on the motor efficiency in a 132 frame with a power of 7.5 kW. The parametric analysis was carried out with the computational fluid dynamics method, and the results were used for the multiobjective genetic algorithm (MOGA) optimization study with the highest efficiency and the lowest motor body temperature objectives. The hub height, hub radius, distance to body cover, blade rising angle, fan cover entrance distance, blade edge angle, blade center radius, blade edge radius, blade end radius, and center edge distance were selected as optimization parameters. 151 simulations were performed. The results showed that the most important parameter for fan efficiency is the hub height which is the parameter that determines the height of the fan impeller diameter. According to the results, the optimum fan design increased the efficiency by 8% compared to the original fan and reduced the winding temperature by 8 °C. The optimized fan design was manufactured and tested against imulation data. This study contributes to sustainable development goals by improving motor efficiency that reduces the cost, designing of new components, and cooling the fan effectively that reduces the amount of copper used.

Enhancing life cycle assessment framework to support product ecodesign through index decomposition analysis

In ecodesign, life cycle assessment (LCA) has not only been used to evaluate a product's environmental sustainability but also serves as a tool for designers to identify areas for sustainability improvement. Conventionally, this is achieved by ranking all contributing LCA variables to identify high-impact areas. However, interpreting and translating this information into actionable design variables can be challenging. An LCA variable can be influenced by multiple design variables, each of which might affect the design's environmental sustainability to varying degrees. Presently, there is a lack of tools capable of analysing the influence of each design variable. To bridge this gap, this study proposes an LCA disaggregation methodology that uses Index Decomposition Analysis (IDA) to assess the environmental sustainability significance of the considered design variables. Using the methodology, designers can make informed decisions that prioritise design effort on design variable with the greatest potential for enhancing the product's environmental sustainability. The proposed methodology is demonstrated through a case study involving the design of a desk fan cover, considering material choice, geometry, and manufacturing process as key design variables.

Numerical Simulation on Flow Field and Design Optimization of a Generator Unit Based on Computational Fluid Dynamics Analysis

Achieving an optimal cooling of the generator unit is indispensable for high working performance. In this work, computational fluid dynamics analysis on the flow field of the conventional type and silent type of the S688CCS series generator unit is conducted, and design optimization of the generator unit with poor cooling is studied based on flow field analysis results. Flow field simulation results indicate that the total cooling air quantity of the silent type generator unit is lower than that of the conventional type generator unit, and the cooling air quantity of the radiator is also lower than that of the conventional type generator unit, which is not conductive for the cooling of the silent type generator unit. The flow field optimization is achieved by adopting the single variable control method to improve the structure of the fan cover, silent components for silence, adjacent structure, and air inlet grille. The corresponding structure optimization scheme is put forward. After optimization, the air quantity for the cooling radiator of the silent type generator unit is 44.33% higher than that of its original structure, and the total cooling air quantity is higher than that of the conventional type generator unit. The research results in this work can provide a theoretical basis for the design of the cooling air flow path of generator units for achieving an optimal cooling performance.

Influence of cold-start time reduction on scooter emissions and fuel consumption over WMTC cycle

Scooters with small displacement air-cooled engine which is technically mature and low cost have been widely used nowadays. Compared to water-cooled engines, the air-cooled engines have nothing like thermostat to speed up warm-up duration. The crankshaft of the air-cooled engine drives the cooling fan coaxially. Thus it starts cooling even at the cold start, which extends the warm-up duration. It harms THC emissions. Many studies have shown that speeding up engine warming up can reduce THC emissions. For a 2-wheel motorcycle of category L3e, in the face of the EURO5 emission standard that was implemented in 2020, the current THC emission of 380 mg/km will be revised down to 100 mg/km, with a reduction ratio of 73.68%, which is the most significant reduction among all polluting gases. Thus, the purpose of this study is to develop a low-cost double-layer fan cover with a function of automatic open and shut. It was installed in a commercially available motorcycle with a raw catalyst for WMTC test. The cooling air was blocked during the cold start, which results in the reduction of 20 s of cold-start time, a period of time from the vehicle starting from ambient conditions to the moment when the engine goes into closed loop mode. Also, the cold phase is reduced by 18.8%, which reduced 12.8% of THC raw emissions and achieved 1.6% fuel economy improvement.

Comprehensive measures to enhance electric heater defrosting (EHD) performance for household frost-free refrigerators

The frost-free refrigerator typically uses a bottom-placed calrod heater to remove frost on evaporator surface. However, the mismatch between full coverage of frost and bottom-up heat transfer extends defrost duration, and warm air intrusion into freezing cabinets (FCs) during defrosting leads to increased FC-temperature rise and overall energy consumption. Therefore, comprehensive measures were applied in this article to enhance defrost performance of the frost-free refrigerator. A special fan cover was adopted which opened during cooling cycles to supply cold air into cabinets normally, but closed during defrosting to block warm air intrusion passage. Moreover, an extra heater (60 W) was inserted in the middle height of the evaporator besides the original bottom one (180 W) to form better frost-heat match. Results show the fan cover and dual heaters altogether reduced defrost duration by 4.5 min and FC-temperature rise by 2.7 °C. Lower FC-temperature after defrost further declined energy consumption for the subsequent recovery cycle, which compensated for its increase for the defrost cycle and dominated the 1.2% reduction in overall energy consumption of the refrigerator. Both measures proved effective in enhancing defrost performance. However, the middle heater may affect cooling cycle performance of the refrigerator, necessitating further investigation.

Reducing cabinet temperature rise during electric heater defrosting of frost-free refrigerators by using a special fan cover to block heat infiltration

Electric heater defrosting (EHD) is effective in removing frost on the evaporator and in recovering capacity/coefficient of performance (COP) for frost-free refrigerators. This study proposes a method of reducing the temperature rise in the freezing cabinet (FC) during the EHD process. Based on the idea of blocking the infiltration passage of the heater-generated warm air, a special cover was designed for the axial fan of the evaporator; the cover was kept open during cooling cycles to supply cold air into cabinets normally, but was forced closed during EHD cycles so that defrost heat was prevented from infiltrating into the FC. Results show that defrost duration was shortened by 3.4%, FC temperature rise within the defrost cycle declined by 1.6 °C, and the overall energy consumption for defrost and recovery cycles altogether was reduced by 1.9% with the fan cover. Further optimization could be made by adjusting the delay of the fan starting after defrosting.

Design of domestic electric oven using uniformity of browning index of bread in baking process

The browning index (BI) represents the color of browning bread and is an important part of the baking process when using a domestic electric oven. Previous studies have developed CFD models for analyzing the baking process, but there are deficiencies in finite element analysis for evaluating the browning of bread. In this study, the uniformity of browning index (UBI) was defined, and a finite element analysis method to reduce the cost and time required for the evaluation of UBI by experiment was suggested for the baking process to develop a new electric oven. The errors of the temperature in the oven cavity and the UBI between experiments and the analysis decreased when using an on/off algorithm for the heater. The CFD results show that the temperature distribution and air flow in the oven cavity are dominant factors in the UBI. The length of the fan cover outlet was designed to reach the performance objective of the UBI less than 12.5 and to control the air flow in the cavity. Baking experiments with the proposed model were performed for verification.

Effects of Geometric Changes at the Fan Side of a TEFC on the Flow and Heat Transfer: A Numerical Study

CFD is performed to study the flow and heat transfer features of a TEFC induction motor. Geometry of an end shield and diameter of the fan cover are varied and examined. The modification of the end shield at the fan side can help increase the flow rate at the loading side by 10% due to a reduction in recirculation between the fan and the end shield. The change of cover diameter can lead to a variation of 40% in the external flow rate at the fan side and around 15% at the loading side. A combination of the re-designed end shield and the fan cover with large diameter is proposed in our study which can lower the average winding temperature by 4°C.

Investigation of Parameters Affecting Heat Transfer and Fluid Flow of a TEFC Electric Motor by Using Taguchi Method

The thermal issue is an important criterion for the design of high efficiency motor. In this study, the numerical simulation on the thermal performance of TEFC electric motor is proposed. The parameters such as fin pitch ratio, fin dimensions and fan cover location relative to the fin are discussed to investigate the effects of them and decrease the winding temperature. In order to examine the various parameters quickly without suffering from a great number of parametric computations, Taguchi method is introduced to reduce the computational effort. The case studies results show the effects of fin and fan cover configuration on average temperature rise of winding. And it is found that the fin pitch ratio has a significant influence on average temperature rise of winding. These case studies not only provide physical insight into the thermal-fluid phenomenon but also find out the optimal combination of parameters from given levels by using SN ratio. An additional simulation is performed and shows a good agreement with predicted value. The new design proposed in this study shows 4.8°C decrease in average temperature rise of winding.

The Validation of Numerical Methodology for Oven Design Optimization Using Numerical Simulations and Baking Experiments

In this paper, we will present the validation of numerical methodology for the improvement of baking performance of a forced convection oven. The baking performance will be assessed as the degree of uniformity between browning and temperature distribution in the oven. We found a linear relationship between the experimentally measured grade of browning and the simulated temperature distribution. Six different designs of oven fan cover were compared through numerical simulations, where a time-dependent 3D numerical model with radiative and convective heat transfers mechanism was used. The results were used in a linear model to estimate the grade of browning. The results were validated with the experimental measurements of baked shortbread using an old and improved-upon oven design. The grade of browning was determined experimentally by the colour contrasts method, based on the colour space CIE L*a*b. The results show that the improved fan cover performs better than the existing fan cover.

A Novel Innovative Design Improvement using Value Engineering Technique: a Case Study

Manufacturers around the globe are competing for the identification of innovative value propositions to survive in the competitive and complex market. This paper is intended to investigate implementation of Value Engineering (VE) technique into the product design concept for necessary changes in design of the humidifier system in order to lower unnecessary costs and to increase quality of the product. Humidifiers are used for ventilation and cooling the air at most houses in cities located in hot and dry areas. Value Engineering as a systematic attempt is used to increase efficiency of the product, and optimize the life cycle cost. This leads to a shift from traditional design towards new efficient designs. For this study, an 8 stage job plan is used for VE job plan. In this article, different components of humidifier were analyzed thoroughly and then numerous suggestions were made at the brainstorming sessions. Function Analysis System Technique (FAST) was also utilized at the first stage. Main findings lead to a conclusion that there were more suggestions at the brain storming session. Main findings lead to a conclusion that best suggestion for improved design of the humidifier is change the material of fan cover from galvanized iron to hard plastic or fiber plastic.

Flow Field Analysis and Optimization Design of Fan Cover for the Duct System of the Split Air Conditioner’s Outdoor Unit

The green characteristic of household split air conditioners can be inproved by reducing the noise or improving the energy efficiency. Therefore, a finite element model of outdoor units duct system was built with Fluent considering the coupling of separated components. Based on the simulation results, the flow field of duct system was analyzed, and the structure of fan cowl was optimized to decrease the export eddy. Experiments were done to proved the effectiveness of the modelling and optimizing process.

707 薄肉の筐体に伝わる振動による騒音に関する研究 : 振動源を支持するファンカバーの打抜形状による騒音の変化(OS10-2 音と振動の解析・制御技術2,オーガナイズドセッション:10)

707 薄肉の筐体に伝わる振動による騒音に関する研究 : 振動源を支持するファンカバーの打抜形状による騒音の変化(OS10-2 音と振動の解析・制御技術2,オーガナイズドセッション:10)

Active and relict alluvial fans on contact karst of the Vrhpoljska brda hills, Slovenia

Several types of contact karst are found within the Slovenian karst, but the most common is the ponor type, which usually develops at boundaries between flysch and limestone. One of these types is in the area of Vrhpoljska brda. In this contact karst area two types of alluvial fans appear on carbonate bedrock. Members of the first type are ordinary alluvial fans with active alluvial processes where flysch derived sediment covered limestone surface in a distinct fan shape. The other type, described as relict alluvial fans, is fan-shaped features preserved in the carbonate bedrock. These essentially bedrock landforms developed as a result of the gradual removal of pre-existing alluvial fan cover and the concurrent but non-uniform chemical denudation of the underlying carbonate bedrock. Geomorphologic and morphometric description of alluvial fans and relict alluvial are provided in the article and mechanisms of relict alluvial fans formation and transformation are discussed.

Airflow and thermal conductance in a totally enclosed induction motor

AbstractHeat transfer coefficients of air‐cooled fins located on the outer surface of a totally enclosed induction motor were measured. It was found that the heat transfer coefficient decreases in the downstream direction in relation to the outer fins. It was also found that increasing the axial length of the fan cover (i.e., so that the fan cover overlaps the fin) increases the average heat transfer coefficient of the outer fins. Internal airflow induced by the rotor fan inside the motor end‐bracket coincides with the rotational speed of the rotor fan. Airflow velocity between the stator coil end and the housing in the motor is low, so a cooling structure with an inside ventilation passage for airflow was introduced to increase the heat transfer of the stator coil. By using an actual motor, the effect of resin (varnish) between the stator and the motor housing on the thermal‐contact conductance was determined; the thermal‐contact conductance of a motor with resin was 1.58 times higher than that of one without resin. © 2001 Scripta Technica, Heat Trans Asian Res, 31(1): 7–20, 2002

Air Flow and Thermal Conductance ill a Totally-Enclosed Induction Motor.

Heat transfer coefficients of air-cooled fins which located on outer surface of a totally enclosed induction motor were measured. It was found that heat transfer coefficient decreases with fin distance. And it was also found that increasing the axial length of the fan cover(i.e., so that the fan cover overlaps the fin)effectively increases the average heat transfer coefficient of the outer fins. Internal flow induced by the rotor fan inside a bracket coincides with the rotational speed of the rotor fan. Flow between the stator coil end and the housing in the motor is small, so a cooling structure with an inside ventilation passage for air flow effectively increases the heat transfer of the stator coil. The effect of resin(varnish)between the stator and the motor housing on the thermal-contact conductance was also investigated by using an actual motor. The thermal-contact conductance of the motor with resin was 1.58 times higher than that of the motor without resin.

Noise Control of Portable Generator Set

Major noise sources in a noisy portable I.C. engine driven generator set have been identified. The generator set engine is petrol start and kerosene run. The exhaust silencer of the engine was providing substantial insertion loss. The separation of engine combustion and mechanical noise indicated that their contribution was almost equal. Since generally combustion noise is more than mechanical noise, the main noise sources we re considered to be mechanical in nature. Sound intensity measurements we re performed to identify major noise sources in the generator set when the exhaust was ducted away. The results of these measurements indicated that the main sources of noise in the generator set are: cooling fan cover, silencer shell, silencer cover and the engine crankcase. Noise control measures were applied to these parts. Sound pressure and power levels we re measured before and after the application of noise control measures. Constrained layer damping treatment and stiffening of the cooling fan cover had a combined effect of reducing the sound pressure level by about 3 dB(A). Rigid clamping of the silencer also reduced the noise level. A partial enclosure was designed for the generator set. The partial enclosure reduced the sound pressure and power levels by about 4 and 3.7 dB(A) respectively. There was an increase in the engine cylinder head temperature due to the enclosure, but the increase in temperature was considered to be safe. An overall noise reduction of 8.5 dB(A) was obtained on side 4 of the generator set as a result of the implementation of all the noise control measures. The noise reduction on the other sides of the generator set was also substantial.

Noise control of engine driven portable generator set

Major noise sources in a noisy portable I. C. engine driven generator set have been identified. The generator set engine is petrol start and kerosene run. The exhaust silencer of the engine was providing substantial insertion loss. The separation of engine combustion and mechanical noise indicated that their contribution was almost equal. Since generally combustion noise is more than mechanical noise, the main noise sources were considered to be mechanical in nature. Sound intensity measurements were performed to identify major noise sources in the generator set when the exhaust was ducted away. The results of these measurements indicated that the main sources of noise in the generator set are: cooling fan cover, silencer shell, silencer cover and the engine crankcase. Noise control measures were applied to these parts. Sound pressure and power levels were measured before and after the application of noise control measures. Constrained layer damping treatment and stiffening of the cooling fan cover had a combined effect of reducing the sound pressure level by about 3 dB(A). Rigid clamping of the silencer also reduced the noise level. A partial enclosure was designed for the generator set. The partial enclosure reduced the sound pressure and power levels by about 4 and 3.7 dB(A), respectively. There was an increase in the engine cylinder head temperature due to the enclosure, but the increase in temperature was considered to be safe. An overall noise reduction of 8.5 dB(A) was obtained on side 4 of the generator set as a result of the implementation of all the noise control measures. The noise reduction on the other sides of the generator set was also substantial.

Soundproof type engine working machine

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