Fan Housing Research Articles

An innovative noise reduction blower fan housing design used in electronics cooling

Electronic devices are equipped with blower fans as a means of removing the heat that accumulates in them. This type of fan operates smartly by increasing the speed of the impeller as the electronic devices become overloaded. When the speed of the motor increases, it creates unwanted noise that may be harmful to the ears of the user. Therefore, it is imperative to reduce this noise while maintaining the same dimensions of the fans. The purpose of this work is to demonstrate how critical measurements can be used to improve the design of blower fan housings. By making a change in the housing of the fan, this study proposes an innovative solution to the noise problem associated with heat radiation fans. A punch has been added to the new housing of notebook system, which may be located on either the upper or lower sides. A punch should be located at the air inlet on the fan's air outlet side, between 0 and 90°. Moreover, a punch should have a height ranging from 0.3 to 1 ​mm and a circle size ranging from one eighth to one fourth. Additionally, the details of noise measurement are presented. The results of the study showed that the noise reduction was enhanced by more than 2 ​dB(A) which can either result in a performance enhancement by increasing the flow rate to reach the same flow rate as the original fan or in a decrease in human discomfort by lowering the noise level. The work has been patented under patent numbers TWM624190U, and CN216554487U.

Pneumatic conveying plant for sorting fruits and root crops

The article deals with the classification of sorting fruits and root crops. When reviewing existing structures, their shortcomings were identified. The authors proposed a new design of the sorting device. The basic principle of operation of this design is based on the creation of a suction air flow inside a metal pipe. The device consists of a container with unsorted fruit, a corrugated plastic pipe of variable length with a tip, a clamp attached to a square metal pipeline. Inside this pipeline there are three rectangular holes of different sizes equipped with gates are fixed. In the lower part of the adapters, cyclones with corrugated plastic pipes of variable length with tips are fixed, descending into the corresponding containers. A protective mesh is installed in the rear part of the metal pipeline and a fan housing is attached, inside which the fan itself is located, driven by an electric motor and creating a suction air flow. The proposed device makes it possible to simplify the design, reduce the consumption of materials, reduce energy consumption, reduce the labor intensity of maintenance, increase productivity, and reduce the degree of damage to the surfaces of sorted fruits and root crops.

Аналіз впливу мотогондоли на силу тяги вентиляторного контуру турбовентиляторної приставки

The subject of this study is the interaction between the engine nacelle of a three-circuit turbojet engine and a turbofan attachment. The object of this research is a model of a cylindrical engine nacelle and a fan part of the impeller of a turbofan attachment. The aim of this study was to evaluate the influence of the engine nacelle on the thrust force of the fan circuit of a three-circuit turbojet engine, taking into account the influence of the operation of the turbofan attachment. Tasks: to simulate the flow around the engine nacelle with a turbofan attachment and without a turbofan attachment; calculate the thrust force of the turbofan attachment. The studies were carried out using the method of numerical experiment. The system of Navier-Stokes equations was closed by the turbulent viscosity model SST Gamma Theta Transitional No. 4. The results of the study showed that the reactive thrust of the fan circuit of the turbofan attachment increases by 0.87-6.15% when operating at an altitude of 0 km, 9 km, 11 km and the range of Mach numbers at the input from 0.2 to 0.5. When flowing around the engine nacelle without taking into account the influence of the turbofan attachment, it is characteristic that the velocity field at the inlet is uniform, except for the zone with a boundary layer near the surface of the engine nacelle. However, during operation of the turbofan attachment, the flow pattern changes radically and the thickness of the boundary layer decreases, and the flow in front of the fan is uneven. A characteristic feature of the turbofan attachment, which is associated with the heating of the intermediate housing between the turbine and fan housings, has a positive effect on reducing the thickness of the boundary layer, wall heating contributes to an increase in the stagnant flow velocity due to viscous forces. The presence of a boundary layer on the engine nacelle does not adversely affect the flow in the fan circuit of the turbofan attachment, and the fan of the turbofan attachment does not adversely affect the engine gas generator. The scientific novelty and practical significance of this work lies in obtaining new data on the effect of the engine nacelle on the thrust force of the fan circuit of a three-circuit turbojet engine, taking into account the influence of the operation of the turbofan attachment. The results obtained can be used to optimize the turbofan attachment of a three-circuit turbojet engine.

The Development of Exhaust Fan Housing With Ceiling Mounting For High Rise Buildings by Using DFMA

Design for manufacturing and assembly (DFMA) is widely applied in many industries to optimize the manufacturing and assembly process at the early stage of design, with the aides of the CAD model. Many researchers apply the DFMA to increase assembly efficiency, by decreasing the number of parts from a product, decreasing the manufacturing cost, and reducing assembly time. Therefore, this research applies DFMA to develop exhaust fan housing with ceiling mounting for high rise building type with the same purpose, and at the same time to justify that the method can overcome the problem of assembly time in a production line. Both designs from before and after the application of DFMA, are being compared by using finite element simulation and experimental. The simulation employs stress analysis, to predict the strength of those designs. While the experimental uses a manufacturing cost survey, real assembly time survey and failure test to show the advantages of DFMA design results. The research result shows that the DFMA method can decrease the manufacturing cost by 0.44%, and the assembly time by up to 2%, and able to withstand the entire mass of the ceiling mounting fan.

Effect of passive and active ventilation on malaria mosquito house entry and human comfort: an experimental study in rural Gambia.

Rural houses in sub-Saharan Africa are typically hot and allow malaria mosquitoes inside. We assessed whether passive or active ventilation can reduce house entry of malaria mosquitoes and cool a bedroom at night in rural Gambia. Two identical experimental houses were used: one ventilated and one unventilated (control). We evaluated the impact of (i) passive ventilation (solar chimney) and (ii) active ventilation (ceiling fan) on the number of mosquitoes collected indoors and environmental parameters (temperature, humidity, CO2, evaporation). Although the solar chimney did not reduce entry of Anopheles gambiae sensu lato, the ceiling fan reduced house entry by 91% compared with the control house. There were no differences in indoor nightly temperature, humidity or CO2 between intervention and control houses in either experiment. The solar chimney did not improve human comfort assessed using psychrometric analysis. While the ceiling fan improved human comfort pre-midnight, in the morning it was too cool compared with the control house, although this could be remedied through provision of blankets. Further improvements to the design of the solar chimney are needed. High air velocity in the ceiling fan house probably reduced mosquito house entry by preventing mosquito flight. Improved ventilation in houses may reduce malaria transmission.

从藩府看朱有燉文学创作之条件

从藩府看朱有燉文学创作之条件

ЧИСЛЕННАЯ МОДЕЛЬ ОГНЕНЕПРОНИЦАЕМОСТИ ЭЛЕМЕНТОВ ГАЗОТУРБИННЫХ ДВИГАТЕЛЕЙ ИЗ АЛЮМИНИЕВЫХ СПЛАВОВ

For the early stages of design, a numerical model of fire resistance and fire permeability of GTE elements made of alu-minum alloys is proposed. The numerical model is based on the solution of three-dimensional Navier-Stokes equations, closed by a two-parameter isotropic SST – turbulence model. We used an implicit pressure solver and a scheme of second-order accuracy in High Resolution space, which allows lowering the approximation order to the first in the areas of solution discontinuities and high gradients to increase the monotonicity and stability of the solution. Additionally, to achieve the solution stability, the High Speed Numerics solver option was used, activating the solver settings Gradient Factor Relaxation = 0.1 and Blend Factor Relaxation = 0.1. The mathematical model for the thermal-hydraulic calculation was set up in the formulation of the coupled heat transfer, taking into account radiation based on the discrete transfer model of the Participating Media. The influ-ence of the degree of blackness on the results of the numerical model is investigated and the most rational radiation model is chosen. The numerical model was validated according to the results of engineering tests on the fire permeability of the plate not cooled by the air flow using a kerosene burner NexGen of the bench Ts17-G3 of FAU P.I. Baranov TsIAM. The obtained results of calculations on fire permeability are comparable with the experimental data both quantitatively and qualitatively. The developed un-steady numerical model of fire permeability of flat plates of aluminum alloys under conditions of free convection can be used in the de-sign of the fan housing by selecting the most rational structural and layout solutions, such as the thickness of the housing, the presence of fire protection coating, cooling intensity, etc.

ВИБРОАКТИВНОСТЬ МАЛОШУМНЫХ ВЕНТИЛЯТОРОВ

Low-noise fans are widely used in the sphere of human life for sanitary and technological purposes. Creation of low-noise fans is currently an advanced scientific and technical area. In some fields of their application, reduced vibrations and noises are of paramount importance not only in terms of sanitation and health, but also from a scientific point of view. This work presents a comparison of the quality of low-noise fan development depending on the selected resistance type. The efficiency of the damping of mechanical system (a low-noise fan) vibrations according to the type of resistance moment used is confirmed analytically and practically. Nowadays, a number of fan types implemented in hundreds of designs have been developed and are in service. In this work, the whole variety of the produced nomenclature of low-noise fans is reduced to two basic types – axial and radial. The paper reports that to ensure minimum noise in the operating mode of the low-noise fans presented in the work, a wideband vibration damper is needed as a required functional unit, and the walls of the fan housing should be sandwich-like with layers made of sound absorbing, sound insulating, and vibration damping materials.

Heat Requirements of Two Layer Strains Placed on Different Dates

ABSTRACT This study was conducted to calculate the heat requirements of Hy-line W-36 and Hy-line W-98 layer chicks placed on different dates, and to select one of these strains based on heat requirements and egg prices. An environmentally-controlled, mechanically-ventilated, and fan and pad-cooled house with a capacity of 94,500 chicks was designed. Based on the identification of September as the month with the highest egg prices, placement dates were selected (16th of March, 1st of April, 16th of April, 23rd of April and 1st of May) to coincide with economic egg weight in that month. The heat requirements for a rearing period of 35days of both evaluated strains starting on the above-mentioned dates were calculated using heat and moisture balance method commonly used for livestock and poultry houses. Those placement dates corresponded to economic egg weight dates (with 50-52 g eggs) of 15th of August, 1st of September, 16th of September, 23rd of September and 1st of October. Total heat requirements during the 35-day rearing periods of chicks placed on the identified dates were respectively calculated as 640, 601, 413, 401 and 369 kW/h for Hy-line W-36 and respectively as 778, 732, 551, 539 and 497 kW/h for Hy-line W-98 chicks. September had the highest egg prices for both strains (4.73 and 5.06 US cents/egg). The lowest heat requirement was observed when chicks were placed on the23rd of April. Hy-line W-36 chicks presented higher total heat requirement than Hy-line W-98 chicks. Therefore, 23rd of April as the most economic placement date and Hy-line W-36 as the most cost-effective layer strain.

EFFECTS OF INLET CLOSURE LEVEL ON VIBRATION CHARACTERISTICS OF A MODIFIED CENTRIFUGAL FAN

Inlet is one of the key parameters that plays an important role in a centrifugal fan. The change of parameters in an inlet can cause static and dynamic pressures in the fan housing. As a consequence, high turbulence can produce vibration. The aim of this research is to study the inlet closure level effects on the vibration characteristics of a modified centrifugal fan. The Inlet closure levels consist of 0; 25; 50; 75; 85; 100% that were tested to examine the vibration characteristic value (x, m, k, Ck, C). The test used a randomized complete design with full factorial experiment. Data analysis employed variance and regression analysis. The results show that the inlet closure effect is significant to the value of the vibration characteristics. The increase of the inlet closure level can cause the quadratic decrease of the values of the vibration characteristics. In addition, the increase of the inlet closure level had no impact on the applied resonance frequency levels. These experimental results obtained the highest values of the vibration characteristic at the inlet closure level of 25%.

An Innovative Approach to Mechanical Product Designs - A Case Study on Computer Cooling Fan Design

With advances in various technologies, it is critical to create a product styling design that can trigger consumers’ willingness to buy. Various studies have been emphasizing on product styling designs that can grasp a consumer’s mind. Average people at this information age have higher demands toward product designs. When considering a purchase, people’s first consideration is whether a product is of high quality at a lower price. Product competitions on the market are affected interactively by globalization and localization and the awareness of humanization and personalization. The conventional black box design approach makes it difficult for a designer to meet consumer demands effectively. Via the framework of mechanical product innovation design approach in this study, patent specifications were reviewed and analyzed in order to decompose the essential elements and their corresponding functions. Correlation tables were built and product structural formula could be determined. More functions were included by replacing elements in order to achieve the completeness of the structural formula. For demonstrating the benefits of this approach, the design of computer cooling fan housing was chosen as a case study. The results indicated that the proposed design approach can effectively assist in the development of product innovative designs.

Development of high-performance and low-noise axial-flow fan units in their local operating region

Aerodynamic and aeroacoustic performances of an axial-flow fan unit are improved by modifying its housing structure without changing the fan blade. The target axial-flow fan system is used to lower temperature of a compressor and a condenser in the machine room of a household refrigerator which has relatively high system resistance due to complex layout of structures inside it. First, the performance of the fan system is experimentally characterized by measuring its volume flow rate versus static pressure using a fan performance tester satisfying the AMCA (Air Movement and Control Association) regulation, AMCA 210-07. The detailed structure of flow driven by the fan is numerically investigated using a virtual fan performance tester based on computational fluid dynamics techniques. The prediction result reveals possible loss due to radial and tangential velocity components in the wake flow downstream of the fan. The length of the fan housing is chosen as a design parameter for improving the aerodynamic and aeroacoustic performances of the fan unit by reducing the identified radial and tangential velocity components. Three fan units with different housing lengths longer than the original are analyzed using the virtual fan performance tester. The results confirm the improved aerodynamic performance of the proposed three designs. The flow field driven by the proposed fan unit is closely examined to find the causes for the observed performance improvements, which ensures that the radial and tangential velocity components in the wake flow are reduced. Finally, the improved performance of the proposed fan systems is validated by comparing the P-Q and efficiency curves measured using the fan performance tester. The noise emission from the household refrigerator is also found to be lessened when the new fan units are installed.

Green Design and Manufacturing of Premium Efficiency Motor

YE3 series of premium efficiency three-phase asynchronous motors adopt computer integrated system and anticipate the best optimized electrical design. In the structure design, airflow validity is analyzed by finite-element method (FEM) and the motors fan is designed optimally through experimental results; on the fan housing, the Ansoft finite-element method is used in analyzing the electromagnetic field , and designing optimally electromagnetic environment with the test results; the finite-element method is also used in analyzing the temperature field, connecting with the test results to optimize the ventilation structure. The radiating rib is metrical distribution and arrangement along the diameter of axle direction on the motor housing, following the principle of heat radiation and the principle of fluid mechanics, which can improve the ventilation and cooling effect. The design of the motor has reached the international advanced level.

COMPARISON OF GEOMETRIC PRECISION OF PLASTIC COMPONENTS MADE BY SUBTRACTIVE AND ADDITIVE METHODS

The paper presents information on manufacturing processes of plastic components. Basic subtractive and additive methods are described. There were also manufactured elements of fan housing by using this two types of methods. Then, the elements were measured using a touch probe. The obtained results were analyzed, on which a comparison of components’ geometric accuracy was performed.

A fuzzy matchmaking approach for Semantic Web Services with application to collaborative material selection

A critical step in the process of reusing existing WSDL-specified services for building web-based applications is the discovery of potentially relevant services. However, the category-based service discovery, such as UDDI, is clearly insufficient. Semantic Web Services, augmenting Web service descriptions using Semantic Web technology, were introduced to facilitate the publication, discovery, and execution of Web services at the semantic level. Semantic matchmaker enhances the capability of UDDI service registries in the Semantic Web Services architecture and it is able to recognize various degrees of matching for Web services. Based on the Semantic Web Service framework, semantic matchmaker, specification matching and probabilistic matching, this paper proposes a fuzzy matchmaking approach for Semantic Web Services to support a more automated and veracious service discovery process in collaborative manufacturing environments. In the proposed approach, the membership function is set up on the semantic information annotated on WSDL specification of a web service, and the similarity of service objects is evaluated by the similarity degree of service attributes. A collaborative material selection case study in the die casting process for thermoelectric fan housing is used to illustrate the proposed approach.

Respostas fisiológicas e produtivas de vacas holandesas em lactação submetidas a diferentes ambientes

Este trabalho foi realizado, no verão de 2002, com o objetivo de avaliar a influência de alguns recursos de climatização na produção de leite e na termorregulação dos animais. Foram utilizadas 10 primíparas e 17 multíparas em lactação, distribuídas em instalação controle (ICO), instalação com nebulizador associado a ventiladores (ICL) e instalação com tela de sombreamento (IT). A produção de leite e o consumo individual foram medidos diariamente para cada animal. A temperatura retal foi medida três vezes ao dia, em três animais de cada instalação; a temperatura de superfície da pele, três vezes ao dia em todos os animais; e a freqüência respiratória, duas vezes ao dia em todos os animais. Os dados climáticos de cada instalação foram registrados e posteriormente calculados os índices de temperatura e umidade (ITU) e de globo negro e umidade (ITGU). Foram selecionados e analisados 26 dias com entalpia elevada. O ITU entre 75 e 76, apesar de considerado estressante por diversas fontes da literatura, não foi associado à condição de estresse pelos animais. As multíparas da instalação climatizada apresentaram freqüência respiratória e temperatura de pele significativamente menor em relação às multíparas das demais instalações. As primíparas apresentaram freqüências respiratórias e temperaturas retais mais altas que as multíparas, nos horários mais quentes do dia. A maior produção de leite das multíparas foi observada no tratamento com tela.

A Computational Fluid Dynamic Analysis of Gas and Particle Flow in Flame Spraying

The flame spraying process, which is a common industrial thermal spraying application, has been analyzed by means of three-dimensional computational fluid dynamics (CFD) simulations. The process used at the Volvo Aero Corporation for the coating of fan and compressor housings has been modeled. The process uses the Metco 6P torch (Metco, Westbury, NY), which ejects a mixture of acetylene and oxygen at high speed through a ring of 16 orifices to form the flame. A stream of argon gas flowing through an orifice in the center of the ring carries a powder of nickel-covered bentonite through the flame to the spray substrate. The torch is cooled by a flow of air through an outer ring of 9 orifices. The simulation emulated reality closely by including the individual inlets for fuel, cooling air, and injected particles. The gas combustion was simulated as a turbulent, multicomponent chemically reacting flow. The standard, two-equation k-e turbulence model was used. The chemical reaction rates appeared as source terms in the species transport equations. They were computed from the contributions of the Arrhenius rate expressions and the Magnussen and Hjertager eddy dissipation model. The first simulations included several intermediate chemical substances whose predicted concentration agreed favorably with measurements. Later, more simplified simulations incorporated only the global chemical reaction involving the initial and the final products, with corrections to the thermal properties being made to account for the missing intermediaries. The gas velocity and temperature fields predicted by the later simulations compared satisfactorily to those predicted by the earlier, more elaborate, ones. Therefore, the final simulations, which incorporated injected particles, were conducted employing the simplified model with only the global reaction. An in-house finite difference code was developed to calculate particle properties. Allowance was made for elliptical shapes, phase changes, and internal heat transfer with regard to the composite material. The particle velocities and temperatures predicted by the final simulations compared fairly well with experimental results obtained with the optical DPV2000 system.

Measurement of the performance of free-standing filtering extraction units used in the woodworking industry

The filtration efficiency of free-standing dust extractors fitted with filter bags of various types and challenged with wood dust of various grades has been measured. During each test, the air pressure inside the filter bag, the extractor air flow rate and the concentration of dust penetrating the filter bag were monitored. Needlefelt filter bags allowed a limited quantity of dust, usually at a concentration well below the maximum exposure limit (MEL) of 5mgm−3, to penetrate when they were clean and improved greatly as they became loaded with dust. Filter bags made from woven cotton let more dust through. Needlefelt bags with specially coated fibres were no more efficient than standard bags but those with a microporous membrane coating were highly efficient. However, an increase in filtration efficiency during loading was invariably accompanied by an increase in air pressure inside the filter bag and a drop in extractor air flow, all effects being more marked when fine dust was used. Some of the extractors leaked dust from around loosely fitting filter bags and dust collector bags, or through holes in the fan housing, indicating that not all aspects of design are ideal. Tests carried out on bags that had been used for long periods indicated that air entering the filter bag gives rise to an initial high external dust concentration, though this did not usually persist. Periodic cleaning of the bag is recommended. Vacuum cleaning the inside when the bag is removed from the cleaner almost restores its original condition, but results in the generation of large quantities of airborne dust. The use of a tool that fits inside the bag enables cleaning to be carried out effectively in situ without exposing the operator to significant concentrations of airborne dust.

Active noise control

A system for reducing noise of a noise generator such as a fan located in a housing includes a short duct (118) directing air to the fan housing. An input transducer (17) is located in the duct (118) at a position further removed from the fan than cancellation device (18) which is also located in the duct (118). An electronic control device (21) with embedded frequencies (22-25) related to the steady state operation of the fan inputs cancellation signals to the cancellation device (18). The input transducer (17) also responds to the random noise of the fan to provide control signals to the control device (21) for generating signals for the cancellation device (18). The input duct (118) can be multi-cellular with respect to the input transducer (17) and the cancellation device (18).

Volume Flow-Rate Measurements and Scaling Laws for a Transverse-Inlet Multiple-Disk Fan

The air moving capacity of a transverse-inlet multiple-disk fan has been measured experimentally and the results successfully collapsed with a simple scaling law. The disk fan studied was an array of several hundred closely spaced plastic disks that rotated about a common axis inside an approximately semicylindrical housing. A splitter plate lying parallel to the axis of rotation and tangent to the disks separated the inflow and outflow streams. The volume flow rate of air per unit length along the axis of rotation was measured using standard LDV techniques. For disk spacings greater than 1 mm, the volume flow rate was found to be essentially proportional to ωhR3, where ω = radian rotation rate of the disks, h = disk spacing, and R = disk radius. This scaling law was derived from a simple force balance for a small fluid element moving between rotating disks. The Reynolds number of the experiments, ωh3R/ν, was varied from 2 × 102 to 103. In addition, the air-moving capability of the disk fan was found to be nearly independent of the geometrical placement of the rotating disks within the fan housing.