3D CFD model for the analysis of the flow field through a horizontal axis wind turbine (HAWT)

With the world’s growing demand for energy, renewable energy production has become important in providing alternative sources of energy and in reducing the greenhouse effect. This study investigates the aerodynamics and performance of the WG/EV100 micro–Horizontal Axis Wind Turbine (HAWT) using Computational Fluid Dynamics (CFD). The complexity of VAWT aerodynamics, which is inherently unsteady and three-dimensional, makes high-fidelity flow models extremely demanding in terms of computational cost, limiting the analysis to mainly 2D Computational Fluid-Dynamics (CFD) approaches. This article explains how to perform a full 3D unsteady CFD simulation of HAWT. All main parts of the WG/EV100 HAWT were designed in SOLIDWORKS. Only the blade design was reverse engineered due to the unavailability of the CAD model and the complexity of its geometric characteristics. The impeller blade is scanned using a Coordi-nate Measuring Machine (CMM), and the obtained 3D scan data are exported from the PC-DMIS software to GEOMAGIC design X to obtain a CAD model of the blade

3D CFD model for the analysis of the flow field through a horizontal axis wind turbine (HAWT)

With the world’s growing demand for energy, renewable energy production has become important in providing alternative sources of energy and in reducing the greenhouse effect. This study investigates the aerodynamics and performance of the WG/EV100 micro–Horizontal Axis Wind Turbine (HAWT) using Computational Fluid Dynamics (CFD). The complexity of VAWT aerodynamics, which is inherently unsteady and three-dimensional, makes high-fidelity flow models extremely demanding in terms of computational cost, limiting the analysis to mainly 2D Computational Fluid-Dynamics (CFD) approaches. This article explains how to perform a full 3D unsteady CFD simulation of HAWT. All main parts of the WG/EV100 HAWT were designed in SOLIDWORKS. Only the blade design was reverse engineered due to the unavailability of the CAD model and the complexity of its geometric characteristics. The impeller blade is scanned using a Coordi-nate Measuring Machine (CMM), and the obtained 3D scan data are exported from the PC-DMIS software to GEOMAGIC design X to obtain a CAD model of the blade

Analiza utjecaja faktora rizika na pojavnost subkliničkog mastitisa na nekim farmama mliječnih krava na istoku Alžira

In order to study the effect of various risk factors on the prevalence of subclinical mastitis, we studied the prevalence of subclinical mastitis in 104 dairy cows (416 udders) from 18 bovine herds in three wilayas in eastern of Algeria using the California mastitis test (CMT) combined with bacteriological analysis. The aim of this research was to determine the effect of 27 risk factors related to the animal, its environment and milking practices on prevalence, as well as the effects of breed, age, stage of lactation, housing and litter type, hygiene level, season, mil production, vacuum level and elimination of first jets on subclinical mastitis frequency. A survey was carried out to collect data on cow numbers, breeds, type of breeding, housing, litter and the level of hygiene in farms, the method of milking and milking practices. The CMT combined with bacteriological examination was performed to detect subclinical mastitis, the Chi 2 test was used to test for difference between the means. Prevalence values were: 24% by CMT vs 17% by bacteriology analysis. Concerning udders, we recorded a rate of 10% vs. 8.7% respectively. The results of the survey show that the Holstein breed is the most exploited and affected (P<0.05). The number of dairy cows varied from 3 to 20 cows. In this study, 56% of cows were raised on farms built of cinder blocks, which had a lower rate compared to farms built of wood and reeds (P<0.001). Animal housing consisting of a concrete floor 33% vs. 36% raised with straw bedding and were more affected (P<0.001), litter is removed only once a day for 13% of cows, which is a factor that predisposes cows to this disease. The frequency is higher during early and late compared to mid-lactation phases (P<0.05); low udder conformation and the right side of udders also had an impact on this disease alongside animal hygiene (P<0.05), and cattle producing more than 12 litres per day were more susceptible (P<0.05). However, the frequency of mastitis was only slightly modified by the lactation number of cows. High and low vacuum level of milking machines and pulsation frequency predisposed cows more to this disease (P<0.05). In this study, cows milked manually were significantly more affected (P<0.05) particularly in summer and the winter, showing high rates (P<0.05).Da bismo uočili učinak različitih faktora rizika na prevalenciju subkliničkog mastitisa, ispitali smo prevalenciju subkliničkog mastitisa u 104 (416 vimena) mliječnih krava iz 18 stada goveda koja se uzgajaju u tri provincije (wilaya) u istočnom Alžiru. Ispitivanje smo proveli pomoću kalifornijskog testa za mastitis (CMT) u kombinaciji s bakteriološkom analizom. Cilj je ovog istraživanja bio utvrditi učinak 27 faktora rizika povezanih sa životinjama, njihovim okolišem i praksom mužnje na prevalenciju, kao i učinak pasmine, dobi, faze laktacije, vrste staje i stelje, razine higijene, godišnjeg doba, proizvodnje mlijeka, razine vakuuma i eliminacije prvih mlazova na učestalost subkliničkog mastitisa. Provedena je anketa u svrhu prikupljanja podataka o broju krava, eksploatiranim pasminama, vrsti uzgoja, staje, stelje i razini higijene na farmama, metodi mužnje i praksom mužnje. Proveden je CMT test u kombinaciji s bakteriološkim testiranjem za detekciju subkliničkog mastitisa. Chi 2 test je rabljen da bi se provjerila razlika između sredstava. Vrijednosti prevalencije bile su: 24 % prema CMT-u u usporedbi sa 17 % prema bakteriološkoj analizi. U svezi s vimenima, zabilježili smo stopu od 10 % u usporedbi s 8,7 %. Rezultati ankete pokazali su da je holstein pasmina najeksploatiranija i najviše zahvaćena (P<0,05); broj mliječnih krava varira od 3 do 20 krava. U ovoj studiji 56 % krava uzgajano je na farmama izgrađenima od opeke i one su imale najniže stope mastitisa u usporedbi s farmama izgrađenima od drva i trske (P<0,001). Staje za životinje imaju betonski pod za 33 % (životinja) u usporedbi s 36 % uzgajanih na podlozi od slame koje su bile više zahvaćene (P<0,001); stelja se podiže jednom na dan za 13 % krava, a to je uvjetovalo krave na ovu bolest. U usporedbi sa sredinom laktacije (P<0,05) učestalost je veća u ranoj i kasnoj laktaciji, niska morfologija vimena i desna strana vimena su utjecale su i na ovu bolest, uz higijenu životinja (P<0,05). Krave koje su proizvodile više od 12 L/dan bile su prijemčivije na bolest (P<0,05). Međutim, učestalost mastitisa malo je modificirana brojem laktacija krava. Visoki i niski vakuum strojeva za mužnju, učestalost impulsa više je uvjetovalo krave na ovu bolest (P<0,05). U ovoj studiji, krave koje su ručno mužene značajno su više bile pogođene ovom bolesti (P<0,05), posebice ljeti i zimi, pokazujući veće stope bolesti (P<0,05)

Computational investigation of vibration characteristics analysis for industrial rotor

During the operation of a rotor, various types of vibrations appear in this mechanical system and often limit the performance and endanger the safety of the operation. Therefore, dynamic analysis is essential because precise knowledge of the vibration behaviour is essential to ensure proper operation. This article presents a set of scientific techniques for the modelling and simulation of rotor vibrations. To work out the equations of the vibratory movement of the rotor, we used the energy approach of Lagrange. To achieve this, a model with one blading wheel carried by a shaft supported by two hydrodynamic bearings is chosen basedon the characteristics of the rotor studied (Fan 280 cement draft fan). It is an arduous task to manually ascertain the analytical resolution of the differential equations that characterise the vibratory behaviour of the rotor. The numerical approach employing the finite element method, programmed on the ANSYS software, made it possible to perform the vibration analysis of the rotor. First, the FAN 280 cement draft fan rotor is modelled using SolidWorks 3D software and reverse design using the coordinate measuring machine (CMM) for the design of the fins. Then, the modal characteristics of the fan rotor model were analysed using the finite element analysis (FEA) software ANSYS Workbench. Also, to study the effect of blade wear on critical speeds, the Campbell diagram was obtained. Finally, harmonic analysis was performed to determine the amplitude of the rotor vortex at critical speeds obtained with and without blade wear