High-speed Fan Research Articles

Design and Analysis for Higher Torque Constant of Brushless Motor for High Volume Low Speed Fan

This paper deals with the design and analysis for torque constant characteristics of Brushless AC motor (BLAC) for High Volume Low-Speed Fan (HVLS). The torque constant characteristic of a BLAC motor is important to ensure higher torque performance concerning the input current. Through a previous study, the necessity of torque constant characteristic of BLAC to achieve optimum performance motor is still limited. Therefore, this paper aims to analyze the torque constant characteristic of BLAC for HVLS fan applications. Three models of BLAC motor with finite permanent magnet volume and magnetomotive force (MMF) have been simulated in order to evaluate the performances of BLAC motor. Commercial Finite Element Analysis (FEA) known as Flux 2D has been used to compute the back-electromotive force (Back-EMF), cogging torque, and transient torque in order to analyze the torque constant characteristic of different slot and pole numbers. As a result, the design of the BLAC motor for 18/20 has been chosen due to higher torque constant compared to others. As a conclusion, this research provides guidelines and an overview of designing a BLAC motor for HVLS fan application.

Study on dump truck dumping process and dust extraction device design

The particle diffusion and movement rules of the dump truck dumping material are simulated in Fluent based on the gas-solid two-phase flow theory. The simulation results show that the dust generation mainly occurs in two stages. One is that when the particle flow is falling, the particle diffusion mainly concentrates on the back of the particle flow. The other is that when particle flow collides with the contact surface, dust diffusion occurs in the area where the collision point is consistent with the outflow direction. According to the simulation results, a dust extraction device for dump truck is proposed to capture dust generated into the atmosphere. The influence of three representative factors: ambient temperature, shape of the dust collection port, fan speed on the performance of the dust extraction device is studied by means of orthogonal experimental design. The results show that the use of plain multiple slot suction port and higher fan speed can improve the dust removal effect and work efficiency of the dust collection device.

Comparative study on performance of high volume low speed (HVLS) fans with high-speed fans for the use in dairy barns

Proper ventilation in dairy barns is important in the summer as high temperatures and the accompanying heat stress can affect the health of the livestock. Although, high speed fans have been in use for a long time to cater to the needs of cooling, HVLS (High Volume Low Speed) fans have proved to be worthy of attention. The cooling effect of the large diameter HVLS fans were compared with that of high speed conventional drum fans in a simulated space using CFD models of the setups at their respective high rotational speeds. This particular work employs MRF (Moving Reference Frame) technique within the CFD simulation. The performance of both these setups were analysed at different heights and distances in order to meticulously compare the performance of the two setups more accurately. The air velocities from the HVLS fans were only slightly less than the high speed drum fans at a distance of 1 m while at increasing distances, the HVLS fan remained more effective than the high speed fans. Also, the HVLS fans covers larger area with more uniform airflow than the high speed fans.

Analysis of the Effect of Inlet Velocity on Cooling Speed in a Refrigerated Container using CFD simulations

The use of refrigerated containers continues to increase rapidly in line with global trade, this kind of container is commonly used to deliver perishable cargo from producers to consumers over great distances, even between continents. To avoid perishable goods from damages, the temperature inside refrigerated containers was controlled and maintained to keep the cooling performance. The purpose of this study is to investigate the effect of variation inlet velocity on the cooling speed inside a refrigerated container. This study was conducted through a computational fluid dynamic simulation validated with experimental results. The simulation was carried out on the variations of inlet velocity based on low-speed fan mode at 4 m/s equal to 32 circulations/hour, and high-speed fan mode at 10 m/s equal to 80 circulations/hour. The results of the simulation show that the greater the inlet fan speed, the faster the cooling speed. The finding of this study is the cooling speed time of high cube refrigerated container with the low-speed fan is 28 minutes and the high-speed fan is 40 minutes.

Analysis on EMF characteristics for torque ripple reduction in BLAC motor intended for HVLS fan application

This paper analyzes the harmonic characteristics of electromagnetic force (EMF) in Brushless Alternating Current (BLAC) motor for High Volume Low Speed (HVLS) fan application. Vibration and noise are one of the main crucial things in HVLS fan application. It comes from torque ripples which can be detected by harmonics of Electro Magnetic Force (EMF). Commonly, there are a few methods to eliminate the noise and vibrations issue, but most literatures only focus on small motor and not intended for HVLS fan application. Thus, the objective of this paper is to eliminate the harmonics content in EMF at early stage design. Through EMF harmonics the expected torque produced could be used to select proper slot-pole number in order to eliminate the noise and vibrations issue. In here, the analysis involves three different slot-pole numbers which are 18s/20p, 12s/10p and 9s/8p BLAC model, respectively. All models have similar volume of permanent magnet. The analysis is carried out using FLUX 2D Finite Element Analysis (FEA) for EMF computational and transient torque computation. Later, Fast Fourier Transform (FFT) analysis is used to calculate the harmonics of EMF. The analysis stage includes the EMF parameter analysis, harmonics and torque ripples analysis. It was found that 18s/20p has higher output torque with the lowest 5% torque ripple value. As a conclusion, this paper presents low torque ripple in point of view of the EMF characteristics in designing HVLS fan.

Steady-State Performance Prediction for a Variable Speed Direct Expansion Air Conditioning System Using a White-Box Based Modeling Approach

When using a certain type of Heating, Ventilation & Air Conditioning (HVAC) systems, it is primary to obtain their steady-state operating behaviors for achieving a better indoor thermal environment. This paper reports a development of a white-box-based dynamic model for a direct expansion (DX) air conditioning (A/C) system to predict its steady-state operating performance under variable speed operation. The established model consists of five sub-models, i.e., a compressor, an electronic expansion valve, an evaporator, a condenser and a conditioned space. Each sub-model was developed based on partial lumped parameter approach. Using the available data generated from an experimental DX A/C system, both transient and steady-state behaviors predictions agreed well with the experimental ones. With the help of the validated white-box model, the inherent steady-state operating performance expressed in terms of the relationship among total cooling capacity (TCC), equipment sensible heat ratio (E SHR) and coefficient of performance (COP) under various speed combinations of compressor and supply fan were further examined. The results show that a higher COP could be achieved when the DX A/C system was operated at a higher fan speed or a lower compressor speed for dealing with a larger required E SHR. This model could be helpful for A/C system design and controller development.

A sequential approach for achieving separate sensible and latent cooling

Abstract Separate sensible and latent cooling (SSLC) is a potentially beneficial approach to improve the efficiency of air conditioning systems; however, the complex configuration of existing and proposed SSLC systems increases installation and maintenance costs, limiting their widespread use in new construction and building retrofit opportunities. In this paper, a sequential SSLC system is proposed to realize the separation of sensible and latent loads by switching a single vapor compressor cycle between two modes (low-SHR and sensible only). This effect is achieved by applying readily available variable-speed equipment at a high compressor speed and a low fan speed to achieve the low-SHR mode operating for dehumidification. This is followed by a sensible only mode to cool the air, which is achieved through a low compressor speed and a high evaporator fan speed. To predict the performance of a sequential SSLC system, a numerical model has been developed and validated. Using this numerical model for energy consumption and optimization studies, it is found that the sequential SSLC system has the potential to save 6.9% to 11.5% energy compared to a traditional cooling system.

Design and Analysis of High Volume Low Speed Fan (HVLS) for Room Size 24m x24m x 18m x

Design and Analysis of High Volume Low Speed Fan (HVLS) for Room Size 24m x24m x 18m x

Optimizing Design of Blades for High-Speed Axial Fans

Optimizing Design of Blades for High-Speed Axial Fans

A parametric fin structure design study for cooling aerospace electro-mechanical actuators with high-speed axial fans

Despite their advantages compared to hydraulic actuators, electric actuators are prone to overheating due to their high heat dissipation. So, developing reliable cooling systems for electric actuators is a crucial task, especially for aerospace applications which require the fulfillment of high safety requirements. In this paper, an air-cooling system utilizing wing bay air is investigated. An axial fan sucks air to flow through a shrouded-fin surface attached to the motor housing. A CFD model is developed to study the heat transfer and air flow processes over the finned surface. The relation between the fan pressure jump with the volumetric flow rate of a high speed SUNON fan at different rotational speeds and ambient pressures is measured in a fan loop and incorporated in the model. To validate the CFD results, a test rig consisting of a finned surface brazed on a heated aluminum cylindrical block and attached to a fan is built. The predicted and measured temperatures at different locations in the aluminum block show good agreement when the numerical simulation is performed using the k-ω-SST turbulence model. The average discrepancy of the predicted and measured steady state temperature differences (T-T∞) reduces from 1.6 °C for the k-e Realizable model to 0.31 °C for the k-ω SST model. Numerical simulation is performed to predict the effect of fin shape, fin number and fin thickness on the cooling performance of the fin structure. The results show that the straight plate fin configuration outperforms the offset-strip and corrugated fin. Also, it is found that there is an optimum value for the fin number, and this optimum fin number changes with the fan rotational speed and ambient pressure. Reducing the solidity of the fin structure by reducing the fin thickness results in improving the thermal performance when the fan operates at a low ambient pressure (0.2 atm). By comparing all data, it is found that the straight fin structure with 110 fins and fin thickness 0.2 mm is the optimum one. For fan speed of 12,000 rpm, this structure can restrict the thermal resistance between 0.17 °C/W at 0.2 atm and 0.047 °C/W at 1.0 atm.

Improvement on dehumidifier performance using a plastic assisted condenser

This paper proposed a new design concept for improving daily moisture removal rate and energy-efficiency factor of a dehumidifier. The plastic straws with diameters of 12 mm, 8.0 mm and 6.0 mm are inserted between the evaporator and condenser as an assisted condenser. A total of four cases are experimentally investigated, and the numerical analysis is conducted to further explain the performance improvement mechanism. Compared to the original dehumidifier, the assisted condenser with twelve straws having a diameter of 12 mm can pronouncedly improve the moisture removal rate of the dehumidifier by 6.9–9.2% and 1.2–6.4% at the standard condition and over-loading condition, respectively. By reducing the straw diameter to 8.0 mm, the improvement is reduced and the assisted condenser even reveal deteriorated effect at a high fan speed condition. Yet more pronounced degradation is seen when introducing 8.0 mm straws having two rows with staggered layout. It can be explained from numerical analysis that the pressure drop across the assisted condenser plays an important role. The optimum design depends on the balance between the main airflow, entrained airflow, and the flow resistance of the assisted condenser.

A High-Speed Wide Fan in Approximate Reverse Carry Propagate Adder for Energy Efficient DSP Applications

A High-Speed Wide Fan in Approximate Reverse Carry Propagate Adder for Energy Efficient DSP Applications

Модификация математической модели напряженного состояния лопаток быстроходных осевых вентиляторов для горной промышленности

Модификация математической модели напряженного состояния лопаток быстроходных осевых вентиляторов для горной промышленности

Influence of casing contouring on flutter boundaries of a jet engine fan

This paper describes a detailed flutter analysis of fan casing contour modifications on a scaled high-speed fan to investigate the influence and effect on flutter boundaries. The flutter analysis focusses on discrete selected members from a previous multidisciplinary study of an automated aero-acoustic optimization with respect to the overall engine performance. The aerodynamic baseline performance of the high-bypass ratio fan is validated with measured rig data using Reynolds-averaged Navier–Stokes (RANS) CFD simulations. Flutter stability predictions are based on the energy method in traveling wave and influence the coefficient formulation using a multi-passage fan assembly in a wide engine operating range. Transonic stall flutter occurs for the first bending mode of blade vibration at part speed, where a few design members show an increased stabilizing aeroelastic behavior especially at approach flight condition. In contrast to that, the results indicate a destabilizing flutter stability effect for certain casing designs at cruise speed related to higher mass flows near choke, which is identified as a transonic unstalled flutter type. Aerodynamic key parameters for the flutter onset mechanism have proved to be the shock/boundary layer interactions in tip region of the fan suction side, which leads to flow separation. A second mechanism is driven by the additional blade vibration in combination with the interaction of shock and tip clearance flow as well as the incoming flow.

Investigation on Gaseous and Particle Mass Emissions from Automatically Fired Small Scale Heating System under Laboratory Conditions

This study presents the experimental results on gaseous and particle mass emissions obtained from a bottom feed pellet stove of 2.5 kW output in part load heat and 5 kW output in nominal heat. The experiments were conducted in a stove manufacturing plant in the southern part of Belgium. Two combustion experiments (A and B) in part load heat output and four experiments (C, D, E and E) in nominal load were performed at three combustion phases: startup, combustion and burnout phase. The pellet stove was operated in different fan speeds varied from 900 rpm to 1250 rpm for the combustion experiments. Experiments A and B were operated with low speed fan, C and D with medium speed fan, E and F with high speed fan. The emissions results include CO2, CO, O2 and particle mass concentrations are presented in this study. A performance analysis in terms of combustion efficiency together with different losses of the pellet stove is also discussed. The experimental results show that CO emissions obtained from the main combustion phase of the part load heat output experiments varied from 1215 mg/Nm3 to 1450 mg/Nm3, while in the nominal load heat output varied from 50 mg/Nm3 to 145 mg/Nm3. Also, the results show that CO emissions in the burnout phase from all the experiments were significantly higher than that in the startup phase followed by the combustion phase. The finding shows that higher CO emissions in the startup and burnout phase have influence on the total CO emissions. Particle mass emissions obtained from the combustion experiments operated with high fan speed varied from 10-15 mg/Nm3 respectively and were much lower than the required limit value of standard EN14785 and other works. The combustion efficiency obtained from all the experiments for the low speed fan, medium speed fan and high speed fan was 92.8±1.2 %, 92.4±1.1 % and 92.7±1.2 % respectively and satisfied the required limit value of the standard.Article History: Received Sept 12th 2017; Received in revised form March 17th 2018; Accepted April 26th 2018; Available onlineHow to Cite This Article: Obaidullah, M., Bram, S. and De Ruyck, J. (2018) Investigation on Gaseous and Particle Mass Emissions from Automatically Fired Small Scale Heating System under Laboratory Conditions. Int. Journal of Renewable Energi Development, 7(2), 111-121.https://doi.org/10.14710/ijred.7.2.111-121

Engineering Novel Lab Devices Using 3D Printing and Microcontrollers.

The application of 3D printing and microcontrollers allows users to rapidly engineer novel hardware solutions useful in a laboratory environment. 3D printing is transformative as it enables the rapid fabrication of adapters, housings, jigs, and small structural elements. Microcontrollers allow for the creation of simple, inexpensive machines that receive input from one or more sensors to trigger a mechanical or electrical output. Bringing these technologies together, we have developed custom solutions that improve capabilities and reduce costs, errors, and human intervention. In this article, we describe three devices: JetLid, TipWaster, and Remote Monitoring Device (REMIND). JetLid employs a microcontroller and presence sensor to trigger a high-speed fan that reliably de-lids microtiter plates on a high-throughput screening system. TipWaster uses a presence sensor to activate an active tip waste chute when tips are ejected from a pipetting head. REMIND is a wireless, networked lab monitoring device. In its current implementation, it monitors the liquid level of waste collection vessels or bulk liquid reagent containers. The modularity of this device makes adaptation to other sensors (temperature, humidity, light/darkness, movement, etc.) relatively simple. These three devices illustrate how 3D printing and microcontrollers have enabled the process of rapidly turning ideas into useful devices.

Numerical simulation methodology of multi-layer Kevlar 49 woven fabrics in aircraft engine containment application

ABSTRACTA numerical simulation method was developed to provide effective tools to estimate the ballistic resistance of Kevlar 49 fabric for gas turbine engine containment system in LS-DYNA. Material model based on representative unit cell and three-element viscoelastic constitutive equation was employed to describe the dynamic response of single-layer and multi-layer fabrics. The influences of mesh size, hourglass control method in the material model were discussed. The numerical simulation method is used to predict the ballistic performance of Kevlar fabrics in testing condition. The failure mechanism, the stress wave propagation and energy absorption mechanism were investigated and compared with testing results and achieved good agreements. It is indicated that the developed numerical method provides promising results in modelling the high-speed ballistic impact events and engine fan blade off events.

Interaction and scattered mode measurement in a mixed bypass/core duct with multiple rotating sources

The rotating rake mode measurement system was developed and implemented at the NASA Glenn Research Center in the 1990s to measure turbofan duct acoustic modes. The system is a radial rake with distributed microphones that is inserted into the duct and continuously rotates about the centerline. The rotating rake mode measurement system provides a complete map of the acoustic duct modes present in a ducted fan and has been used on a variety of test articles: from a low-speed concept test rig to full-scale production turbofan engines. Prior rotating rake mode measurement system measurements have occurred in environments with a single rotating source interacting with a stationary source to produce duct modes at the fan rotor harmonics. A recent test of a scale model high-speed research fan in the NASA 9 × 15 ft Low Speed Wind Tunnel had two rotating sources, a rotor fan and a booster fan, on the same shaft. The interaction of the two rotating sources generated scattering at the harmonic sum and difference tones, and modal scattering at a given fan harmonic. Rotating rake mode measurement system data were acquired from this high-speed fan model which provided a database to allow for validation of the duct mode analysis technique expansion and experimental evidence of the scattering phenomenon. In this paper, modes from the two different sources and associated stationary surfaces from a sample fan condition were reported and compared to analytical predictions, in order to validate the ability of the rotating rake mode measurement system to measure scattered modes. Sample modal content of the booster fan tone and its harmonics tones are presented as well as the sum and difference interaction between the rotor and booster fans.

Assessment of Sugarcane Billet Harvester on Recovery of Sweet Sorghum Biomass for Ethanol Production

Sweet sorghum (Sorghum bicolor L. Moench) is a promising bioenergy crop for the production of ethanol and bio-based products. Sugarcane billet harvesters can be used to harvest sweet sorghum. Multiple extractor fan speed settings of these harvesters allow for separating the extraneous matter in the feedstock, which has been associated with increased milling throughput and better juice quality at the processing facility. This removal is not completely selective, and some stalk material is also lost. These losses can be higher for sweet sorghum than sugarcane due its lower weight. This paper presents an assessment of how the speed of the primary extractor fan of a sugarcane billet combine used for harvesting sweet sorghum affects the biomass yield, biomass losses, and quality at delivery for the production of ethanol from extracted juice and fiber. Three primary extractor fan speeds (0, 800, and 1100 rpm) were evaluated. Higher fan speeds decreased fresh biomass yields by up to 28.3 Mg ha−1. Juice quality was not significantly different among treatments. Ethanol yield calculated from sweet sorghum harvested at 0 rpm was 6075 L ha−1. This value decreased by about half for material harvested at 1100 rpm due to the differences in biomass yield.

Performance Comparison of Destratification Fans for Large Spaces

Ceiling fan is proven to have a beneficial effect on increasing air velocity and reducing temperature stratification and thus saving energy for high ceiling applications. Studies show that the velocities produced by large diameter, ceiling mounted fans do not produce a negative or positive effect on human comfort. Recently, smaller, high velocity fans have been introduced to the market as an alternative to these large diameter fans that provides similar energy savings due to reduced destratification, while still not moving the air fast enough to cause human discomfort, though these products have been studied less. This study simulates and compares the performance of both large and small diameter fans using a validated computational fluid dynamics (CFD) model. Two different types of destratification fans are investigated for their performance in destratifying the air temperatures in warehouse style retail stores. A portion of a retail store is used as a base to create the test environment. Simulations show that the small diameter high speed fan (SDHSF) is very good at bringing a well-mixed column of air all the way to the floor, but the spaces without a fan directly overhead are hardly affected. The large diameter low speed fans (LDLSF) are able to mix nearly the entire space, though they created uncomfortable drafts near head height. Between these two fans, the LDLSF is more successful at destratifying the entire space, though the SDHSF is better at only destratifying a specific, smaller area. Varying the speed of the LDLSF also allows for successful destratification, while maintaining acceptable draft velocities.