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This review paper based on the study of different type of solar air heater with baffled fin and without using baffle fin. It has been observed that the thermal efficiency of baffled duct type solar air heater is higher than smooth duct solar air heater. Highest thermal performance advantage in wide range of air flow rate. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. Study and analysis of roughness and operating parameters on heat transfer. The study has covered the range of Reynolds number Re depending on types of the configuration of the solar collectors. Based on the values of Nusselt number Nu have been determined for different values of configurations and operating parameters. To determine the increase in heat transfer and increment in thermal performance, the values of Nusselt have been compared with those of smooth duct and baffled fin under similar flow conditions. The enhancement is attributed to the heat transfer increases due to the perforated baffles on the absorber plate and reduction in the mean absorber plate temperature. Vivek Singh | Ajay Singh | Ashish Verma "A Review on Experimental Analysis of Double Pass Solar Air Heater With Baffled Absorber Plate" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-6 , October 2017, URL: https://www.ijtsrd.com/papers/ijtsrd3556.pdf

Методика уніфікації відцентрових компресорних машин. Опис конструкції повітродувок. Порівняльна оцінка та вибір оптимального варіанту повітродувки. Газодинамічний розрахунок базового варіанту. Розрахунок витікань через ущільнення повітродувок. Розрахунок осьової сили. Розрахунок критичного числа обертів ротора. Розрахунок підшипників на довговічність. Уніфікація модельного ряду повітродувок. Розробка програмного забезпечення для газодинамічного розрахунку повітродувки. Охорона праці. Методика унификации центробежных компрессорных машин. Описание конструкции воздуходувок. Сравнительная оценка и выбор оптимального варианта воздуходувки. Газодинамический расчет базового варианта. Расчет утечек через уплотнения воздуходувок. Расчет осевой силы. Расчет критического числа оборотов ротора. Расчет подшипников на долговечность. Унификация модельного ряда воздуходувок. Разработка программного обеспечения для газодинамического расчета воздуходувки. Охрана труда. Method of unification of centrifugal compressor machines. Description of the design of the blowers. Comparative evaluation and selection of the optimal blower option. Gas-dynamic calculation of the basic version. Calculation of leakage through the seals of blowers. Axial force calculation. Calculation of the critical rotor speed. Calculation of bearings for durability. Unification of the blower range. Development of software for gas-dynamic calculation of the blower. Occupational Safety and Health.

European Directives 2002/44/EC and 2003/10/EC establish the exposure limit values for preventing operators&rsquo, risks to vibration and noise transmitted by machines. Few studies studied noise and vibration of agricultural backpack powered machines (as mist blowers and blowers), but nobody critically studied them. This work analyzed the field back vibration, hand-arm vibration (HAV), and noise transmitted to ten operators by eight blowers and mist blowers. Unweighted and weighted vibration were analyzed, using the standards ISO 2631-1 (back), and ISO 5349-1 and ISO/TR 18570 (hand-arm system). The noise was evaluated by recording the acoustic pressure level at the operators&rsquo, ears using the ISO 9612. With the ISO 2631-1, the vibration to the operators&rsquo, back was low (0.38 ms&minus, 2), but the unweighted vibration measured along y and z-axes (not used by the ISO 2631-1) were high (&gt, 11 ms&minus, 2). HAV were also low when using the ISO 5349-1 (the highest value was 2.51 ms&minus, 2 in mist blowers), but high with the ISO/TR 18570 for the onset of vibration white finger (1446 ms&minus, 1.5 in blowers). Noise levels were always high: more than 100 dB(A), excluding the blower with the exhaust inside the blower hose. This last machine had noise levels lower than 86 dB(A), but its specific feature could increase environmental pollution.

Магістерська дисертація на здобуття ступеня магістра за освітньо – професійною програмою підготовки на тему : «Реконструкція котельні науково-виробничого підприємства «Укроргсинтез» у м.Київ » : 106 с., 7 рис., 23 табл., 3 дод., 21 джерело, 8 креслеників формату А1 , 2 кресленики формату А2. Об’єкт розробки – котельня. Мета розробки – розробка проекту твердопаливної котельні з контактним водонагрівачем для теплопостачання промислової будівлі . Наведені розрахунки теплового навантаження котельні та теплової схеми котельні. Виконані гідравлічні розрахунки трубопроводів. Виконаний розрахунок димової труби. Вибране основне та допоміжне обладнання котельні: котел, вентилятори, насоси, теплообмінники. Розроблена схема автоматизації котельні. Передбачені заходи з охорони праці. Розроблений стартап проект , в результаті техніко-економічних розрахунків показано, що використання твердопаливної котельні є більш економічним ніж котельні на природному газі. Master 's dissertation for obtaining a Master' s degree in an educational - professional training program on a subject : " Boiler house reconstruction of scientific-productional enterprice “Ukrorgsintez” in Kyiv ": 106 p., 7 pic., 23 tabl., 3 adds ., sources 21 ., 8 drawings format А1, 2 drawings format A2 . The property development - boiler room. The purpose of development - development Total project boiler for heating industrial building. Contains calculations of heat load boiler and thermal circuit . Completed pipeline hydraulic calculations and aerodynamic airways. The calculation of the chimney. Go to the main boiler and auxiliary equipment, heaters, fans, pumps, heat exchangers. Contains startup project, result of technical-economic calculations is solid fuel boiler that more economical that gas boiler. The scheme of automation boiler. The measures for safety. Completed feasibility calculations. Магистерская диссертация на получение степени магистра по образовательно - профессиональной программе подготовки на тему: «Реконструкция котельной научно-производственного предприятия« Укроргсинтез »в г.Киев»: 106 с., 7 рис., 23 табл., 3 доп., 21 источник, 8 чертежей формата А1, 2 чертежи формата А2. Объект разработки - котельная. Цель разработки - разработка проекта твердотопливной котельной с контактным водонагревателем для теплоснабжения промышленного здания. Приведенные расчеты тепловой нагрузки котельной и тепловой схемы котельной. Выполнены гидравлические расчеты трубопроводов. Выполнен расчет дымовой трубы. Выбрано основное и вспомогательное оборудование котельной: котел, вентиляторы, насосы, теплообменники. Разработанная схема автоматизации котельной. Предусмотрены мероприятия по охране труда. Разработан стартап проект, в результате технико-экономических расчетов показано, что использование твердотопливной котельной является более экономичным чем котельной на природном газе.

In addition to safety, small hand-operated forestry machines can be criticised for affecting the operators’ health, especially because of high levels of exhaust gas emissions, noise and vibrations. In this study, gas emissions, noise and hand-arm vibrations (HAV) levels have been measured on chainsaws, hedge cutters and blowers fuelled with two different types of fuel: a commercial RON 95 gasoline with the addition of 2% of synthetic oil suitable for two-stroke engines and, as an alternative, a specific advanced mixture available on the market, based on alkylate gasoline. For two different running conditions, i.e. with the engine at idle speed and when executing a typical working routine (maximum speed with load), tests were carried out for: Þ gas emissions, using a gas analyser, for measuring the volatile organic compounds (VOC) values Þ noise, using a sound level meter, to record the levels at both of the operator’s ears Þ HAV, using a tri-axial accelerometer fixed on the handgrip(s) of the machines. The results demonstrated that, when using the alkylate fuel, the VOC emissions were reduced, in the considered machines, from 23 to over 77%, while for noise and HAV, the differences in level were not statistically significant. The present study confirms that the reduction in the amount of emissions can be remarkably improved by adopting advanced fuels that lead to a more efficient combustion process.

Bu çalışma; Gebze İleri Biyolojik Atıksu Arıtma Tesisinde havalandırma ünitesindeki oksijen ihtiyacı için harcanan elektrik enerjisinin azaltılması ve arıtma sisteminin toplam işletme maliyetinin düşürülmesi amacıyla yapılmıştır. Çalışan bir ileri biyolojik kentsel atıksu arıtma tesisinde tesisin giriş parametrelerine bakılarak havalandırma ünitesinde harcanan elektrik enerjisi için havalandırma ekipmanları (blowerler) arasında karşılaştırmalar yapılarak yeni kurulan havalandırma sisteminin ekonomik analizi yapılmıştır. Gebze İleri Biyolojik Atıksu Arıtma Tesisinde tesisinin giriş KOİ, TN, debi, fazla çamur ve enerji sarfiyatı verileri iki yıl boyunca kaydedilmiş olup bu veriler ışığında tesisin iki farklı ekipman ile harcadıkları elektrik enerjisi ilişkileri incelenmiştir. Arıtma tesisinde; % 93 AKM, % 90 KOİ, %95 BOİ5 giderim veriminin gerçekleştiği gözlenmiştir. Buna göre yapılan hesaplarda, tesiste manyetik yataklı turbo blowerlerin kullanılmasıyla havalandırma ünitesindeki enerji tüketiminin yaklaşık % 30 oranında azaldığı görülmüştür. Anahtar Kelimeler : Arıtma Maliyeti, Atıksu, Blower, Enerji Optimizasyonu This study was done to reduce the total operating cost of the treatment system and reduction of the electricity consumed for the oxygen requirement in the ventilation unit of the Gebze Advanced Biological Wastewater Treatment Plant. Economic analysis of the newly established ventilation system was made at a running advanced biological urban wastewater treatment plant by looking at the input parameters of the plant and by comparing the ventilation equipment (blower). The input COD, TN, flow, excess sludge and energy consumption data of the plant in the Gebze Advanced Biological Wastewater Treatment Plant have been recorded for two years and In this light, the electrical energy relationships that the plant spends with the two different equipment have been examined. At the treatment plant; 93% SSM, 90% COD 95% BOD5 removal efficiency has been observed. According to the calculations made, the energy consumption of the ventilation unit has been reduced by about 30% using magnetic bearing turbo blowers. Keywords : Treatment Cost, Wastewater, Blower, Energy Optimization

Создана математическая модель для моделирования и проектирования подъемного комплекса амфибийного судна на воздушной подушке (СВПА), которая позволяет вычислять параметры подъемного комплекса СВПА в различных режимах его эксплуатации. Зависимости, представленные в математической модели, дают возможность рассчитать давления воздуха в жестких и гибких ресиверах подъемного комплекса, в секциях воздушной подушки и необходимый напор нагнетателей. Допустимо определение расходов воздуха в гибкий ресивер носового, кормового и бортовых гибкого ограждения, а также из секций воздушной подушки в атмосферу., Створено математичну модель для моделювання і проектування підйомного комплексу амфібійного судна на повітряній подушці (СППА), яка дозволяє обчислювати параметри підйомного комплексу СППА в різних режимах його експлуатації. Залежності, представлені в математичній моделі, дають можливість розрахувати тиски повітря в жорстких і гнучких ресиверах підйомного комплексу, у секціях повітряної подушки і необхідний напір нагнітачів. Припустимо визначення витрат повітря в гнучкий ресивер носового, кормового і бортових гнучкого огородження, а також із секцій повітряної подушки в атмосферу., A mathematical model for simulation and designing of the hovercraft’s lifting complex has been developed. The mathematical model allows calculating the parameters of the hovercraft’s lifting complex in different modes of its operation. The equations presented in the models allow calculating the air pressure in both rigid and flexible receivers of the lifting complex, in the sections of the air cushion, as well as the required pressure of blowers. Furthermore, it is possible to determine the air flow rates in the bow, stern and side flexible receivers, as well as the air flow rate from air cushion sections to the atmosphere.

Auxiliary components of the SOFC system (reformer, anode gas recirculation device) were investigated. In the hybrid system all devices will be operated with different biogases. The influence of biogas on the devices was investigated theoretically and experimentally.

Komunalne čistilne naprave (KČN) omogočajo čiščenje odpadne vode do zadovoljive kakovosti, primerne za izpust v naravo. V KČN si sledi vrsta različnih postopkov čiščenja. Eden izmed njih je biološko čiščenje, kjer se kisik umetno dovaja v aeracijske bazene. Za dovajanje kisika obstajajo različne vrste puhal in difuzorjev, ki za obratovanje potrebujejo veliko energije in posledično prinašajo visoke obratovalne stroške. Kadar se načrtuje gradnja čistilne naprave je pomembno, da bo dosegala visoko stopnjo čiščenja in da bo ekonomsko učinkovita, kar pomeni, da bo obratovala s čim manjšimi obratovalni stroški. Diplomsko delo podaja primerjavo različnih puhal in difuzorjev za vnos kisika v aeracijske bazene. Podane so prednosti in slabosti uporabe ter primerjava stroškov obratovanja in vzdrževanja različnih puhal in difuzorjev. Posebna pozornost je namenjena primerjavi centrifugalnih puhal, ki so zelo pogosto instalirana v čistilne naprave in novejšim turbo puhalom. Rezultati kažejo, da največje prihranke pri porabi energije in nizke stroške obratovanja omogočajo visoko hitrostna turbo puhala, saj so 10% - 20% energetsko bolj učinkovita. Wastewater treatment plants provide wastewater purification processing to a level of quality that allows its release into the environment. During the treatment in the plant wastewater undergoes various purification processes. In biological purification processes oxygen is typically pumped into aeration tanks in quantities that ensure aerobic decomposition. Various types of blowers and diffusers are used to pump oxygen into aeration tanks - these however require huge amount of energy for operation and it's cost represents high proportion of plant's overall operational costs. Design of wastewater treatment plants needs to ensure plant's overall effectiveness, environmental sustainability and economic efficiency, which includes minimising operational costs. This diploma work compares various blowers and diffusers that are used for oxygen transfer to the aeration tanks. Advantages and disadvantages of various blowers and diffusers are presented, including presentation of operational features and their contribution to the overall cost of plant operation. Thesis focuses in particular to the comparison of centrifugal blowers, which are most commonly used in plants today, and newer turbo blowers. Comparison shows that the largest savings in consumption of energy and consequently largest reduction of operational costs can be accomplished by using high-speed turbo blowers as these provide 10~20% better energy efficiency.

The ring fan is a propeller fan by an axial-flow impeller that has a ring shape shroud on the bladetip side. In this study, the whole flow field of the ring fan is simulated by a CFD code; theaerodynamic noise generated by the fan is predicted based on the wake characteristics. Moreover, theaccuracy of the CFD code has been verified by comparing with the aerodynamic characteristics ofthe propeller fan of a current model. The aerodynamic characteristics of the ring fan by the CFD canrepresent the tendency of the measurement value qualitatively, however, the flow rate in the CFDbecomes 30% lower than the actual measurement value. The main flow domain of the ring fan isformed at the tip side of the blade since the blade tip vortex is not formed at the blade tip side.Therefore, the relative velocity of the ring fan becomes fast due to the circumferential velocity. Thesound pressure levels of the ring fan in the frequency band less than 200 Hz become larger than thepropeller fan. According to the analysis on the wake characteristics, it clarified that (1) Karmanvortex at the main flow domain is shedding in the frequency domain lower than 200 Hz, (2) theaerodynamic sound of the ring fan on the vortex shedding frequency becomes large because of anincrease in the relative velocity and the velocity fluctuations., 長崎大学工学部研究報告, Vol.40(75), pp.17-22 ; 2010

Many studies about the noise and the vibration of the blower are made so far. There are many problems about the noise and the vibration. However, there are little studies about the vibration and noise of a blower used under special environment such as the ship. Therefore, in this study, we examined it about the vibration characteristics of the electric blower which is used on the ship. Then, we investigated the cause of the abnormality phenomenon to occur during the driving of the electric blower.

In the first report, in order to clarify the influence of the cutoff of the scroll casing on the discrete frequency noise, the dependence of the diameter of a cylinder on the discrete frequency noise generated from interaction with the wake of a centrifugal impeller was discussed. From results of the analysis on the interaction noise and flow around the cylinder, a several experimental characteristics have been obtained. In the second report, in order to predict the interaction noise generated from a centrifugal fan, the prediction theory of the noise level based on the wake characteristics of the centrifugal impeller is proposed. In the prediction theory, the drag in the wake of the centrifugal impeller is applied for the periodic fluctuation phenomenon of the momentum on the solid surface of the cylinder. The noise level of the predicted value was able to estimate quantitatively decrease of the interaction noise by the diffusion of the wake., 長崎大学工学部研究報告, Vol.40(74), pp.7-12 ; 2009

In order to clarify the influence of the cutoff of the scroll casing on the discrete frequency noise,the dependence of the diameter of a cylinder on the discrete frequency noise generated from interaction with the wake of a centrifugal impeller is discussed. The discrete frequency noise level decreases when the diameter of the cylinder becomes large. The noise is generated by the pressure gradient at the stagnation point on the cylinder surface formed by the jet-wake flow of the impeller. The domain where the stagnation point vibrates extends when the diameter of the cylinder becomes large; the pressure fluctuation has become small according to the diameter. It is shown that the interaction noise generated from the centrifugal fan can be reduced depending on the design of the cutoff shape.

The ring fan is a blower that has a shroud at the tip side of the axial flow impeller. In this study, to clarify the influence of the flow around the impeller on the aerodynamic characteristics and noise of the fan is aimed. The following characteristics were obtained; the efficiency of the ring fan is improved about 13% than the current propeller fan, the specific noise level is reduced approximately 6dB. The potential of the blade tip vortex of the ring fan has been weakened by the shroud. The blade tip vortex of the ring fan is generated at outside of the diameter of the impeller; the relative flow is attached to the blade surface by the weakened tip vortex. From these results, the overall characteristics of the fan improved by the decrease of the relative velocity.

本研究では、回転翼上の非定常圧力の計測法を確立し、貫流羽根車翼上の圧力の基本特性を明らかにする。具体的に述べると、複雑なケーシングのない簡単な形状を有する貫流羽根車を対象として、動翼表面の非定常圧力測定を試みる。そして、その結果を、流れの可視化、および、粒子画像速度計(以後PIV)による測定、熱線流速計(以後HW)による測定、数値計算による結果と比較し、考察する。その結果、位相平均手法を用いることで、一周期間の翼表面での圧力変動を明らかにした。本実験結果は、数値解析のベンチマークとしても有効であろう。, In the present research, we develop the measuring technique of unsteady pressure on a rotating blade surface, and reveal the basic features of a cross-flow-impeller pressure. Specifically speaking, we consider the simplest model for the fundamental study, namely, the flow around the cross-flow impeller rotating with flat-plate blades in open space without any casings. On this impeller's blade, we measure the fluctuating pressures, which are discussed in comparison with flow visualizations with the particle-image velocimeter (PIV), velocity measurements by a hot-wire velocimeter (HW) and numerical simulations. As a result, we get accurate pressures on the rotating blade, which are conditionally-averaged over a number of periods. The obtained experimental results can be also dedicated to CFD as standard benchmarks.

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The multi-blade fan, which has been widely used as a blower for air-conditioning systems of vehicles, is one of the well-established fluid machinery. However, many factors must be considered in its practical design because the flow generated in the fan is quite complicated with three-dimensionality and unsteadiness. The fundamental fan performance is primarily determined by the impeller of the fan, and is also affected by the scroll casing. However, the theoretical estimation of the effect of the casing on the performance has not been well established. In order to estimate the casing effect on fan performance, detailed three-dimensional (3D) flow analysis in the casing is necessary. Stereoscopic PIV (SPIV) is one of the useful techniques for experimental analysis of 3D flow fields. There are some difficulties in practical application of SPIV for flow analysis in fluid machinery with complicated geometry, but the results obtained provide useful information for understanding the 3D flow field. In this report, experimental investigation of the flow in the scroll casing has been carried out using PIV and SPIV under the premise of downsizing automobile air conditioner fans.

The crack arose during actual operation, in an impeller of large-sized blower, at the joint part of the main board and blade. For the purpose to clarify this phenomenon, dynamic analysis and static analysis using the finite element method were performed. The analysis results showed that the cause of a crack of impeller is the stress which occurs owing to the deformation of the side board by centrifugal force. This deformation is wave like one which is same pitch as blade. Then, the structural modification by pseudo-inverse method was performed for the purpose of stress reduction. In this case, designer does not want the minimum weight optimum design but the minimum modification design. Pseudo-inverse method may modify the structure with the minimum distance in the design variable space to satisfy the stress restriction. Some cases are tried. When the design variables were 3 main parts thicknesses, those are main board, side board and blade, practical solution is deduced for 8 calculations to satisfy the stress limit with 10% weight increase.収録刊行物

Time frequency analysis of the surge onset was performed in the centrifugal blower. A pressure signal was registered at the blower inlet, outlet and three locations at the impeller shroud. The time-frequency scalograms were obtained by means of the Continuous Wavelet Transform (CWT). The blower was found to successively operate in four different conditions: stable working condition, inlet recirculation, transient phase and deep surge. Scalograms revealed different spectral structures of aforementioned phases and suggest possible ways of detecting the surge predecessors.