Fan Rotational Speed Research Articles

Agenator: An open source computer-controlled dry aging system for beef

<h2>Abstract</h2> Dry aging of beef is a process where beef is exposed to a controlled environment with the ultimate goal of drying the beef to improve its quality and value. Comprehensive investigations into the effects of various environmental conditions on dry aging are crucial for understanding and optimizing the process, but the lack of affordable equipment focused on data collection makes it difficult to do so. The Agenator was thus developed as an open source system with a suite of features for investigating dry aging such as: measuring and recording relative humidity, temperature, mass, air velocity, and fan rotational speed; precise control within 1% for relative humidity and 50 rpm for fan rotational speed; robust signal integrity preservation and data recovery features; modular design for easy addition and removal of individual chamber units; and non-permanent fixtures to allow easy adaptation of the system for other applications such as investigating dehydration of food products. The open source system comes with user-friendly computer software for interfacing with the system and creating sophisticated environmental control programs. The Agenator is available to the public at https://osf.io/87nck/.

Fan Flow Field in an Installed Variable Pitch Fan Operating in Reverse Thrust for a Range of Aircraft Landing Speeds

Abstract The installed flow field for a variable pitch fan (VPF) operating in reverse thrust for the complete aircraft landing run is described in this paper. To do this, a VPF design to generate reverse thrust by reversing airflow direction is developed for a representative 40,000 lbf modern high bypass ratio engine. Thereafter, to represent the actual flow conditions that the VPF would face, an engine model that includes the nacelle, core inlet splitter, outlet guide vanes, bypass nozzle, core exhaust duct, aft-body plug, and core nozzle is designed. The engine model with the VPF is attached to a representative airframe in landing configuration to include the effects of installation. A rolling ground plane that mimics the runway during the landing run is also included to complete the model definition. Three-dimensional (3D) Reynolds-averaged Navier–Stokes (RANS) solutions are carried out for two different VPF stagger angle settings and rotational speeds to obtain the fan flow field. The dynamic installed VPF flow field is characterized by the interaction of the freestream and the reverse stream flows. The two streams meet in a shear layer in the fan passages and get deflected radially outward before turning back onto themselves. The flow field changes with stagger setting, fan rotational speed, and the aircraft landing speed because of the consequent changes in the momentum of the two streams. The description of the installed VPF flow field as generated in this study is necessary to (a) qualify VPF designs that are typically designed by considering only the uninstalled static flow field and (b) choose the VPF operating setting for different stages of the aircraft landing run.

Characterization of volatile carbonyl compounds in defective green coffee beans using a fan assisted extraction process

In this work, the characterization of volatile carbonyl compounds profiles in healthy and defective green coffee beans was performed. The objective of this characterization was to identify carbonyl marker compounds related to the main bean defects of both arabica and robusta species (black, sour, immature and bored) in non-aged and aged beans. A simple and innovative procedure for volatile compounds extraction was developed, so that usual heating procedures that may adulterate samples' identity can be avoided. The coffee sample and an acceptor solution containing a carbonyl derivatizing reagent are placed inside a screw-cap flask featuring an inner electric fan. The efficiency of the volatile carbonyl compounds mass transfer could be increased due to the fan's operation. The experimental parameters, fan rotation speed, extraction period and sample mass were studied to improve the volatile compounds extraction before HPLC analysis. Defective green beans showed higher contents of some volatile carbonyl compounds than healthy green beans. The volatile carbonyl compounds profile obtained during the forced ageing assay revealed that butanal, benzaldehyde, 3-methylbutanal and hexanal were, consistently, found in higher amounts in both arabica and robusta defective beans, in comparison with healthy beans of the same lot.

Dynamic Load Balancing Using Actual Workload Traces Based on Central Processing Unit Temperatures

AbstractWith the rapid growth in demand for distributed computing, data centers are a critical physical component of the “cloud.” Recent studies show that the energy consumption of data centers for both cooling and computing keeps increasing, and the growth in server power densities makes it ever more challenging to keep the servers below their maximum operating temperature. This paper presents a new dynamic load-balancing approach based on individual server central processing unit (CPU) temperatures. In this approach, a load balancer assigns a task in real time to a server based on the objective to keep the CPU temperatures below a maximum value. Experimental studies are conducted in a single rack based on production workload traces of Google clusters. This study also compares the performance of this method with two other load balancing approaches, Round Robin, and a CPU utilization-based method in terms of temperature distributions, local fan rotation speeds, system loads, and server processing times. Furthermore, we investigate how the effect of the proposed load balancing changes with different assumed applications run on servers. The results indicate that this new method can more effectively reduce both server CPU temperatures and local fan rotation speed in a rack especially for the most of web applications.

Pengaruh Diameter dan Kecepatan Kipas Kondensor terhadap Suhu AC Mobil

The efficiency of the Air Conditioning (AC) system in a car depends on the process of compression, condensation, and evaporation. The new thought that arises is what if the diameter of the condenser fan blade is varied? The objectives of this study are: (1) to test the effect of the diameter of the condenser fan blade on AC temperature, and (2) to test the effect of condenser fan rotation speed on AC temperature. This research is using an experimental method. The results showed: 1) there was an effect of the diameter of the condenser fan on AC temperature, which was 16.7%; and 2) there is an influence of condenser fan rotation speed on AC temperature that is equal to 20.5%. These findings become a reference that to improve the performance of the AC, it can be done by increasing the heat transfer process in the condenser.

Application of the Symmetric Model to the Design Optimization of Fan Outlet Grills

In this study, different designs of the opening pattern of computer fan grills were investigated. The objective of this study was to propose a simulation analysis and compare it to the experimental results for a set of optimized fan designs. The FLUENT computational fluid dynamics (CFD) simulation software was used to analyze the fan blade flow. The experimental results obtained by the simulation analysis of the optimized fan designs were analyzed and compared. The effect of different opening pattern designs on the resulting airflow rate was investigated. Six types of fans with different grills were analyzed. The airflow velocity distribution in the simulated flow channel indicated that the wind speed efficiency of the fan and its influence were comparable with the experimental model. The air was forced by the fan into the air duct. The flow path was separately measured by analog instruments. The three-dimensional flow field was determined by performing a wind speed comparison on nine planes containing the mainstream velocity vector. Moreover, the three-dimensional curved surface flow field at the outlet position and the highest fan rotation speed were investigated. The air velocity distribution at the inlet and the outlet of the fan indicated that among the air outlet opening designs, the honeycomb shaped air outlet displayed the optimal performance by investigating the fan characteristics and the estimated wind speed efficiency. These optimized designs were the most ideal configurations to compare these results. The air flow rate was evenly distributed at the fan inlet.

Design and implementation of an unmanned aerial vehicle with self-propulsive wing

The article aims to prove the effectiveness of the proposed unmanned air vehicle design (The Propulsive Wing) through numerical and experimental means. The propulsive wing unmanned air vehicle is a completely new class of unmanned air vehicle, making disruptive changes in the aircraft industry. It is based on a distributed cross-flow electric fan propulsion system. When the fan starts to operate, the flow is drawn from the suction surface, provided by energy through the fan and expelled out of the airfoil trailing edge (TE). This causes a significant lift increase and drag reduction with respect to ordinary aircrafts, making it perfect for applications requiring low cruise speed such as firefighting, agriculture, and aerial photography. In this early stage of the investigation, our main aim is to prove that this design is applicable and the expected aerodynamic and propulsion improvements are achievable. This is done through a two-dimensional computational fluid dynamics investigation of the flow around an airfoil with an embedded cross-flow fan near its TE. A scaled wind tunnel model of the same geometry used in the computational fluid dynamics investigation was manufactured and used to perform wind tunnel testing. The computational fluid dynamics and wind tunnel results are compared for validation. Furthermore, an unmanned air vehicle model was designed and manufactured to prove that the propulsive wing concept is flyable. The article shows that the aerodynamic forces developed on the cross-flow fan airfoil are not only functions of Reynolds number and angle of attack as for standard airfoils but also function of the fan rotational speed. The results show the great effect of the rotational speed of fan on lift augmentation and thrust generation through the high momentum flow getting out of the fan nozzle. Wind tunnel tests show that the suction effect of the fan provides stall free operation up to very high angles of attack (40 degrees) leading to unprecedented values of lift coefficient up to 5.8. The flight test conducted showed the great potential of the new aircraft to perform the expected low cruise speed and high angles of attack flight.

Assessing ventilation rate measurements in a mechanically ventilated laying hen facility

Gaseous emission in laying hen facilities affects animal production performance and the environment. Emission is ruled by gas concentration and ventilation rate (VR), which are the key parameters to estimate precise emission factors. In this work, VR were assessed in a mechanical ventilated laying hen facility under Mediterranean climate conditions. The study was performed during a complete production cycle from July 2015 to October 2016. Direct hot wire anemometer (HWA) and fan rotational speed methods, and indirect CO2 mass balance method were used to assess the VR. Mean VR was 5.3 ± 2.9 m3 h-1 hen-1 for the HWA method. The mean uncertainty of VR based on the HWA method was 8.5%, and it varied among ventilation stages from 2.3 to 12.8%. Uncertainty was higher in warm season (9.6%) than in cold season (5.4%). In relation to fan rotational speed method, mean VR was 5.9 ± 3.3 m3 h-1 hen-1, which accounts for 8.3% more than the HWA method. According to the results, the fan rotational speed method would be less sensitive than the HWA method for assessing VR. VR was 6.3 ± 2.1 m3 h-1 hen-1 for the CO2 balance method, which estimated lower VR values in warm season compared to the laser tachometer (LT) method (-5%) but higher values compared to the HWA method (+5%). In contrast, it estimated higher values in cold season compared to the HWA method (+23%) and LT method (+17%). Correlation analysis showed a strong correlation between the CO2 balance method and both direct methods (R = 0.85 and 0.86 for HWA and LT, respectively).

Regulation of the cooling fan rotation speed, as an effective instrument for reducing mechanical consumption of energy

Drawing on the example of engine unit YaMZ-652, by means of calculation, and theoretically, the efficiency of using stepless regulation of the cooling fan rotation speed. The greatest effect from the regulation is achieved in the range of small and average loads of the engine performance at the regimes being tested.

Effect of fan and shroud configurations on underhood flow characteristics of an agricultural tractor

ABSTRACTIn the current study, effects of two different underhood geometry modifications namely; fan position relative to shroud and fan tip clearance, on airflow through an agricultural tractor engine cooling system are investigated by utilizing CFD modeling. For the characterization of each modification, the underhood components are reduced to a domain of cooling systems including only fan, shroud, and radiator that allows saving in computational time and cost. The models are validated using a custom designed underhood flow setup, where hotwire velocity measurements at proximity to the radiator are conducted. The mass flow rate and the uniformity of the airflow through the radiator are quantified as performance parameters. For the former modification, position of fan relative to shroud, the computations are performed for the percentages of fan projection into shroud (FPiS) varying from 78% to 0% at fan rotational speeds of 2060 and 2800 rpm. The optimum fan location is found to be around 56–60% for both rotational speeds that leads 8% increase in mass flow rate compared with the pre-design location of 74%. In addition, a noticeable reduction in the relative magnitude of the RMS velocity through the radiator is obtained for the moderate FPiS values. For the latter modification, fan tip clearance, the computations are performed for the tip clearance values varying from 5.25to 12 mm at a fan rotational speed of 2060 rpm. As the tip clearance decreases up to 6 mm, air mass flow rate can be improved by 7%. However, further reduction in tip clearance does not improve the air mass flow rate instead it decreases, suggesting an optimum tip clearance value. The results suggest that the proper geometrical modifications in engine cooling systems might induce significant improvement in the aforementioned performance indicators.

Numerical analysis of control characteristics of variable refrigerant flow heat-pump systems focusing on the effect of expansion valve and indoor fan

In commercial and office buildings, it has recently become popular to install variable refrigerant flow (VRF) compression-type heat pump systems. In particular, VRF systems with multiple indoor units are being installed in large buildings because such systems have large adjustment capacity. On the other hand, because users of VRF systems can freely choose the number of indoor units to install and can turn indoor units on and off independently, operating conditions are not predictable and it is difficult to find adequate control parameters under wide changes in load. With this background, we are developing a new numerical simulation model based on the laws of physics. Because this model can easily add and delete system elements, we believe that it will be useful for VRF system analysis.In this study, we utilize a numerical simulation model to evaluate both steady and unsteady conditions in VRF systems. In this paper, we focus on the connection between manipulated variables (the expansion valve's open pulse and fan rotational speed) and controlled variables (supply air temperature and the degree of superheating at the evaporator outlet). Moreover, we compare the difference between the performance of a single indoor unit and that of multiple indoor units operating simultaneously.As a result, we can evaluate the dynamic characteristics of manipulated variables and the effect of changing the number of active indoor units, each of which has their own VRF characteristics.

Aerodynamic Similarity Principles and Scaling Laws for Windmilling Fans

Windmilling requirements for aircraft engines often define propulsion and airframe design parameters. The present study is focused on two key quantities of interest during windmill operation: fan rotational speed and stage losses. A model for the rotor exit flow is developed that serves to bring out a similarity parameter for the fan rotational speed. Furthermore, the model shows that the spanwise flow profiles are independent of the throughflow, being determined solely by the configuration geometry. Interrogation of previous numerical simulations verifies the self-similar nature of the flow. The analysis also demonstrates that the vane inlet dynamic pressure is the appropriate scale for the stagnation pressure loss across the rotor and splitter. Examination of the simulation results for the stator reveals that the flow blockage resulting from the severely negative incidence that occurs at windmill remains constant across a wide range of mass flow rates. For a given throughflow rate, the velocity scale is then shown to be that associated with the unblocked vane exit area, leading naturally to the definition of a dynamic pressure scale for the stator stagnation pressure loss. The proposed scaling procedures for the component losses are applied to the flow configuration of Prasad and Lord (2010). Comparison of simulation results for the rotor-splitter and stator losses determined using these procedures indicates very good agreement. Analogous to the loss scaling, a procedure based on the fan speed similarity parameter is developed to determine the windmill rotational speed and is also found to be in good agreement with engine data. Thus, despite their simplicity, the methods developed here possess sufficient fidelity to be employed in design prediction models for aircraft propulsion systems.

Design of an experimental wind tunnel system for control applications

In this study, a low-cost experimental wind tunnel system for evaluation of control algorithms and utilization in teaching activities is presented. The system is designed inspired from conventional wind tunnels and has a basic design and low cost as can be realized in every laboratory. The design of mechanical part and electronics hardware and development of computer software are described in detail. The objective of the control system is to ensure the rotation speed of fan, which is placed at the end of the pipe, and track a desired trajectory by controlling air pressure in the pipe. Experimental results are also presented to demonstrate the performance of the system.

Drying kinetics and characteristics of dried gambir leaves using solar heating and silica gel dessicant

A drying combination of solar heating and silica gel dessicant has been applied to dry gambir leaves. The solar energy is captured by a collector to heat the air and the hot air is used to dry gambir leaves in a drying chamber. An exhaust fan in drying chamber assists to draw water molecules from gambir leaves accelerated by silica gel dessicant. This study has investigated the drying kinetics and drying characteristics of gambir leaves drying. In drying operation the air velocity is tuned by a PWM (pulse width modulation) controller to adjust minimum and maximum level, which is based on the rotation speed of the exhaust fan. The results show that the air velocity influenced the drying kinetics and drying characteristics of gambir leaves using solar-dessicant drying at 40 cm distance between exhaust fan and silica gel dessicant.

Design and experiment of variable rate orchard sprayer based on laser scanning sensor

During different growth periods, canopy size and density in orchards are variable, which need application conditions (flow rate and air flow) to be adjusted to match the canopy’s characteristics. In order to improve orchard sprayer’s automatic operating performance, an automatic variable-rate orchard sprayer (VARS) fixed with 40 electromagnetic valves and 8 brushless fans was developed based on the canopy’s spatial dimensions. Each solenoid valve and brushless motor can be individually adjusted in real-time through pulse width modulation (PWM) signals emitted by a control system to adjust each nozzle’s spout and fan rotation speed. A high-precision laser scanning sensor (light detecting and ranging, LIDAR) was adopted as the detector to measure the canopy volume using the variable rate algorithm principle. Field experiments were conducted in an apple orchard, and conventional air blast sprayer (CABS) and directed air-jet sprayer (DAJS) were tested as a comparison. Results showed that on average, 46% less spraying solution was applied compared to conventional applications, while penetration rate was similar to DAJS. Normalized deposition in the canopy with variable application was higher than that of conventional applications, indicating that electronic sprayers are more efficient than conventional sprayers. It was also observed that VARS could significantly reduce off-target loss. The field experiment showed that the newly developed variable-rate sprayer can greatly reduce pesticide use and protect the environment for the orchard fruit production, and also provide a reference for design and performance optimization for plant protection machinery. Keywords: variable rate, orchard, sprayer, spatial dimension, air volume, flow rate, laser scanning sensor, precision agriculture DOI: 10.25165/j.ijabe.20181101.3183 Citation: Li L L, He X K, Song J L, Liu Y J, Zeng A J, Liu Y, et al. Design and experiment of variable rate orchard sprayer based on laser scanning sensor. Int J Agric & Biol Eng, 2018; 11(1): 101–108.

Implementasi Motode Fuzzy Sugeno pada Pengendalian Exhoust Fan Sebagai Pembersih dan Pengatur Udara

In a special room for smokers, Exhoust Fan is installed to clean the air and keep the room air fresh. Most Exhoust Fan works manually, not set automatically so that it has a constant rotational speed, so the function of the exhaust fan as an air purifier is not optimal. This study aims to apply a fuzzy method as well as to control the speed of the Exhoust Fan. Fuzzy logic will process the carbon monoxide gas which is detected by the MQ-3 sensor then the output decision maker is in the form of the Exhoust Fan rotation speed level which is exactly in accordance with the amount of carbon monoxide read by the MQ3 sensor. fuzzysugeno method can regulate the speed of putan fan based on the amount of carbon monoxide read by the MQ-3 sensor.

Experimental and numerical investigations of indoor air movement distribution with an office ceiling fan

Ceiling fans provide cooling to indoor occupants and improve their thermal comfort in warm environments at very low energy consumption. Understanding indoor air distribution associated with ceiling fans helps designs when ceiling fans are used. In this study, we systematically investigate the air movement distribution in an unoccupied office room installed with a ceiling fan, as influenced by (1) fan rotational speed, (2) fan blade geometry, (3) ceiling-to-fan depth, and (4) ceiling height. We both measured and simulated air speeds at four heights in the occupied zone according to ANSI/ASHRAE/IES Standard 55 (2013) for seated and standing occupants. CFD predictions were validated by experimental results. In general, numerical results show that for an unoccupied space, the fan blade geometry, ceiling-to-fan depth, and ceiling height only influence air speed profiles within a cylindrical zone directly under a ceiling fan whose diameter is identical to that of the ceiling fan. However, the average speeds within the cylindrical zone at each height are very similar (<10% in difference) for the different blade shapes studied, indicating a minor influence of blade geometries on occupants' perception of the thermal environment. The results also indicate that the velocity profile remains similar in the main jet zone (the tapered high-velocity zone under the fan blade) for various rotational speeds. The jet impingement on the floor creates radial airflow at the ankle level (0.1 m) across the room, which is not the most effective airflow distribution for cooling occupants.

Aplikasi Pembelajaran Pengenalan Kriptografi Algoritma Affine Cipher Dan Vigenere Cipher Menggunakan Metode Computer Assisted Instruction

In a special room for smokers, Exhoust Fan is installed to clean the air and keep the room air fresh. Most Exhoust Fan works manually, not set automatically so that it has a constant rotational speed, so the function of the exhaust fan as an air purifier is not optimal. This study aims to apply a fuzzy method as well as to control the speed of the Exhoust Fan. Fuzzy logic will process the carbon monoxide gas which is detected by the MQ-3 sensor then the output decision maker is in the form of the Exhoust Fan rotation speed level which is exactly in accordance with the amount of carbon monoxide read by the MQ3 sensor. fuzzysugeno method can regulate the speed of putan fan based on the amount of carbon monoxide read by the MQ-3 sensor

An intelligent FFR with a self-adjustable ventilation fan

ABSTRACTThis article presents an intelligent Filtering Facepiece Respirator (FFR) with a self-adjustable ventilation fan for improved comfort. The ventilation fan with an intelligent control aims to reduce temperature, relative humidity, and CO2 concentrations inside the facepiece. Compared with a previous version of the FFR, the advantage of this new FFR is the intelligent control of the fan's rotation speed based on the change in temperature and relative humidity in the FFR dead space. The design of the control system utilizes an 8-bit, ultra-low power STC15W404AS microcontroller (HongJin technology, Shenzhen, China), and adopts a high-precision AM2320 device (AoSong electronic, Guangzhou, China) as temperature and relative humidity sensor so that control of temperature and relative humidity is realized in real time within the FFR dead space. The ventilation fan is intelligently driven and runs on a rechargeable lithium battery with a power-save mode that provides a correspondingly longer operational time. Meanwhile, the design is simplistic. Two experiments were performed to determine the best location to place the fan.

Assessment of Noise Variability of Landing Aircraft Using Phased Microphone Array

Enforcing noise control environmental laws around airports is a difficult task due to the large variability in the noise levels observed for flyovers of the same aircraft type under similar conditions. These variations are not properly considered by the current models, such as the noise-power-distance tables. In this research, noise measurements of aircraft flyovers were used to assess this variability and investigate its causes. 115 flyovers of landing aircraft were recorded using a 32-microphone phased array. It was assumed that the main cause of this variability is the change of the emitted aircraft noise, as previous studies showed that the effect of the variable atmosphere (for the distances considered) is negligible. The noise-level variability for the Boeing 737 and Fokker 70 cases was approximately 7 dB. The fan rotational speed of each flyover was determined by analyzing the spectrograms. Functional beam forming was applied to the acoustic data. For the Boeing 737 case, it was found that the engines are the dominant noise source for all flyovers and that over 75% of the variation of the noise levels can be explained by variations in the engine settings. The Fokker 70 flyovers were dominated by airframe noise sources. Differences in the aircraft velocity explain almost 70% of the noise-level variability in this case.