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Blowers are widely used in tasks such as ventilation, exhaust, drying, cooling, heat dissipation, or conveying medium, and they usually consume a lot of energy. There is an inevitable gap between the rotating impeller and static volute casing due to manufacturing tolerance and thermal deformation. The circulating flow in the gap has an important effect on the performance of the blower. In this study, computational fluid dynamics (CFD) was used to investigate the performance of the blower under different flow conditions and gaps, and the accuracy of the numerical simulation was verified by performance experiments. The results show that the flow separation under low flow conditions in the impeller channel can be suppressed by the circulating flow. However, the efficiency of the blower is decreased because a part of the power is used to maintain the circulating flow. Under design conditions, efficiency is reduced by 5.3~8.2%, depending on the gap sizes. Due to the increased flow rate in the impeller channel caused by the gap circulating flow, the net flow rate of the impeller under design conditions is about 12% higher than the inlet flow rate of the blower. Therefore, it leads to an increase of about 12% in impeller efficiency calculated by the net flow rate compared with the inlet flow rate. Finally, the flow field distribution on the impeller channel under different gap conditions was compared, and the effects of the gap on the blower performance were analyzed from the perspective of flow field structure. [ABSTRACT FROM AUTHOR]

Battery electric vehicle (BEV) air conditioning systems often use positive temperature coefficient (PTC) heaters to heat the passenger compartment. The heating process consumes a lot of energy in low-temperature environments, which seriously affects the driving range and user experience. This study aims to reduce the low-temperature energy consumption of the air conditioning system and improve energy efficiency through an innovative optimization method. In this study, the energy consumption composition of the air conditioning system was analyzed, and the goal of minimizing the sum of the total power consumption of the PTC heater and the blower was determined, while the efficiency characteristic of the blower was considered at the same time. The relationship between the average temperature of the passenger compartment measurement points and the PTC power and airflow rate was studied by combining experiments and numerical simulations, and the alternative operating conditions that met the temperature requirement were determined. On this basis, the total power consumption of the air conditioning system was analyzed and optimized. The results show that PTC power, airflow rate, and blower efficiency all have an important influence on the total power consumption of the air conditioning system. The optimized scheme could reduce the theoretical total power from 1315.32 W of the original scheme to 1246.83 W, and the actual total power from 1350.05 W of the original scheme to 1326.56 W, with reductions of 5.21% and 1.74%, respectively. The low-temperature energy consumption optimization method for the BEV air conditioning systems proposed in this study is instructive for the selection of blowers and the design of control strategies for air conditioning systems. [ABSTRACT FROM AUTHOR]

This paper presents a new 4-lobe blower for supercharging a two-stroke engine. Based on a modified Roots compressor manufactured prototype shows pros and cons of an innovative profile. The results demonstrate that the shape of rotor edges effect out pressure stability. The measurement results include the main assessed parameters: outlet pressure, overall efficiency, losses and outlet air temperature.

Regenerative flow machines are known to be simple in construction but complex in flow characteristics. Due to this reason, the design of these machines has been primarily esoteric, and hence its performance heavily relies on the experience and expertise of the designer. Since there are no established rules of thumb for designing them, this paper attempts to provide simple design correlations for systematically designing regenerative flow machines viz. pumps, blowers, and compressors. Three different impeller designs have been considered, namely the (i) single-side vane impeller, (ii) double-side vane impeller, and (iii) peripheral vane impeller, for the three types of machines. More than ten design parameters have been considered for sizing the machines. Experimental and computational data available in open literature have been used to obtain physically meaningful correlations in simple form, and require minimal and practically available inputs. Fluid properties and practical constraints were taken into consideration while deriving the correlations. Constants in the correlations were obtained using least square regression analysis. The accuracy of the obtained correlation is determined by the correlation coefficient. The deviation obtained using the derived correlations varied from 10 to 25%. A consolidated set of correlations has been presented, which will be helpful in making a preliminary design before CFD simulation, design optimization, and prototype building. Finally, the obtained correlations have been used to demonstrate the design of a regenerative flow pump. [ABSTRACT FROM AUTHOR]

The efforts to increase capacity while maintaining the granulation of the grinding process are carried out to maximize the use of the hammer mill machine, which is the second largest electric energy consumption in a plant. The method that can be done to achieve this is by setting the screen position and setting the right blower opening. Standard screen specifications will maximize the capacity of the grinding process and produce optimum granulation. In order to get the maximum grinding capacity, DFCO can be set at the maximum but will have an effect on the motor current during the grinding process, the average current will tend to be high.The aim of this research was to determine the effect of variations in the screen’s and blower’s position settings on the capacity and granulation of raw materials from the grinding process. The usage of 2.5 mm and 3 mm diameters screens, as well as adjusting the screen position of 2.5 mm at the top and 3 mm at the bottom, resulted in better capacity and granulation than using a screen with only 3 mm diameter. The larger the blower and DFCO openings, the greater the grinding capacity, but also increased the motor current. The larger the blower opening, the greater the decrease in the water content of grinding raw materials.

Copyright of Journal of Soil Sciences & Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present study, the authors investigate the simplest model of cross-flow impellers, in order to provide the fundamental flow features of cross-flow impellers. The model is a two-dimensional cross-flow impeller with a very-high aspect ratio, and rotates in stationary fluid. More strictly, we occasionally place a splitter plate with minimal influence instead of casings for more precise observations and measurements. Instantaneous measurements of flow-velocity vectors on the mid-span plane are conducted using a CCD camera and a double-pulse YAG laser with a particle-image-velocimetry technique, in addition to conventional flow visualisations and hot-wire-velocimetry measurements. As a result, the authors show the revolutional motion of such an eccentric vortex as a large-scale re-circulating flow structure inside the cross-flow impeller, and reveal the detail of flow features at Reynolds number Re = 300-2500. Furthermore, the authors show the relations between Re and out-flow rate from the impeller.

Copyright of Journal of Soil Sciences & Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Currently, total electricity consumption of furnaces is unregulated, tested at laboratory conditions using the DOE test procedure, and is reported in the GAMA directory as varying from 76 kWh/year to 1,953 kWh/year. Furnace blowers account for about 80percent of the total furnace electricity consumption and are primarily used to distribute warm air throughout the home during furnace operation as well as distribute cold air during air conditioning operation. Yet the furnace test procedure does not provide a means to calculate the electricity consumption during cooling operation or standby, which account for a large fraction of the total electricity consumption. Furthermore, blower electricity consumption is strongly affected by static pressure. Field data shows that static pressure in the house distribution ducts varies widely and that the static pressure used in the test procedure as well as the calculated fan power is not representative of actual field installations. Therefore, accurate determination of the blower electricity consumption is important to address electricity consumption of furnaces and air conditioners. This paper compares the potential regional and national energy savings of two-stage brushless permanent magnet (BPM) blower motors (the blower design option with the most potential savings that is currently available in the market) to single-stage permanent split capacitor (PSC) blower motors (the most common blower design option). Computer models were used to generate the heating and cooling loads for typical homes in 16 different climates which represent houses throughout the United States. The results show that the potential savings of using BPM motors vary by region and house characteristics, and are very strongly tied to improving house distribution ducts. Savings decrease dramatically with increased duct pressure. Cold climate locations will see savings even in the high static pressure duct situations, while warm climate locations will see less savings overall and negative savings in the high static pressure duct situations. Moderate climate locations will see little or no savings.

A motorized rice de-stoning machine was locally developed for separating stone pebbles from milled rice. Major component being the reciprocating screen coupled with the blower and the hopper. The stone separation is achieved by vertical oscillation of the reciprocating screen coupled with a suction - like air produced by the blower directly beneath the screen causing rice - mixture to float just above the screen and the stones are sucked up the reciprocating screen then discharged through the stone chute and the clean rice collected in opposite order. The de-stoning machine was designed to be powered by a high speed (2980 r min-1) 0.746 kW electric motor. It was evaluated for its efficiencies in terms of rice separation and de-stoning, the tray loss and impurity level after separation were also evaluated. The highest de-stoning efficiency was recorded between 5 to 7 mm feed gates as 99.75% and the lowest was recorded at a feed gate of 20 mm as 82.5%. The highest rice separation efficiency was recorded at 5 mm feed gate to be 98.89% and the lowest of 93.33% was at 20 mm. The highest values of impurity level and tray loss were recorded at 20 mm as 2.041% and 6.67% respectively, while the lowest values were recorded at 5 mm as 0.028% and 1.11% respectively. The capacity also increased as the feed gate increase. All results showed a high correlation with feed gate. [ABSTRACT FROM AUTHOR]

The production of biofuels and biochemicals from biomass-based feedstock, which is one of the most promising strategies for replacing petroleum-based resources and thus alleviating global warming, has received increasing attention in recent years. However, this strategy is energy-intensive due to the low product concentrations after transformation step. In this study, a novel hybrid-blower-and-evaporator-assisted distillation configuration (HBED) was proposed for enhancing process efficiency in bioproduct production from biomass. Several important industrial cases have been investigated to demonstrate the proposed configuration. By applying HBED, light components are partially removed in an evaporator, and the latent heat can be circulated during the process, leading to a substantial improvement in energy efficiency. A blower can increase the energy efficiency of an evaporator significantly, while the combination of an evaporator and blower can substantially reduce the size, capital cost, and operating cost of the distillation column. The results show that the proposed HBED configuration can achieve significant energy savings. Notably, the operating costs can be reduced by up to 45.4%, 26.3%, and 36.7% for the levulinic acid, 2,3-butanediol, and furfural purification processes, respectively. Furthermore, the CO 2 emissions of a conventional column and the proposed configuration are evaluated and compared. [ABSTRACT FROM AUTHOR]

Comparing with the common air cycle heat pumps using electrical machine as the prime mover, an air cycle heat pump with a turbocharger driven by a blower (ACHPTDB) could not only cuts down the initial cost, but also reach a balance between the heating capacity and heating load. The blower is chosen as the prime mover and the turbocharger takes place of the compressor and expansion valve/expander. A thermodynamic model for the ACHPTDB was built by using finite-time thermodynamics (FTT). The performance of the model was optimized associated with the air mass flow rate and subsequent distribution of pressure drops, which indicates the thermodynamic performance can reach its maximum by adjusting the air mass flow rate. It is also shown that heating COP has a maximum with respect to the blower pressure ratio or other parameters, which indicates there exists a tradeoff in how the mass flow rate and the blower pressure ratio should be allocated to make heating COP reach its optimization. [ABSTRACT FROM AUTHOR]

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.

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.

In this paper, we present a study on a jet flow, assisted by low net charge ion wind from bipolar corona discharge setup. The ion wind is simultaneously generated from both positive and negative electrodes placed in parallel, adding momentum to the bulk flow directed alongside the electrodes and focused in the middle of interelectrode space. The electrodes are connected to a single battery-operated power source in a symmetrical arrangement, where the electrode creating charged ions of one polarity also serves as the reference electrode to establish the electric field required for ion creation by the opposite electrode, and vice versa. Multiphysics numerical simulation is carried out with programmable open source OpenFOAM, where the measured current-voltage is applied as a boundary condition to simulate the electrohydrodynamics flow. The jet flow inside the device is verified by hotwire anemometry using hotwires embedded within the device, with the measured values in good agreement with simulation. The corona discharge helped to focus the jet and increased the flow peak velocity from 1.41 m/s to 2.42 m/s with only 27.1 mW of consumed discharge power. The device is robust, ready-to-use and minimal in cost. In addition, as the oppositely charged corona flows are self-neutralized, the generated air flow remains neutral and therefore does not attach to a particular target, which expands the application range. These are important features, which can contribute to the development of multi-axis fluidic inertial sensors, fluidic amplifiers, micro blowers, gas mixing, coupling and analysis with space constraints and/or where neutralized discharge process is required, such as circulatory flow heat transfer or the formation of low charged aerosol for inhalation and charged particle deposition. [ABSTRACT FROM AUTHOR]

Highlights: [•] A quasi-dynamic method is proposed for examination of centrifugal blower. [•] Results are presented in a form of the spectral maps. [•] Maps allow to establish moment of occurrence and frequency of flow phenomena. [•] Surge is preceded by high pressure jumps within inlet zone. [•] Surge frequency is in agreement with the Helmholtz formula approximation. [Copyright &y& Elsevier]

We have investigated the spectra of pressure pulsations in the near field of the open working section of the wind tunnel with a vortex flow behind the tunnel blower formed like the flow behind the hydroturbine of a hydraulic power plant. We have made a comparison between the measurement data for pressure pulsations and the air stream velocity in tunnels of the above type and in tunnels in which a large-scale vortex structure behind the blower is not formed. It has been established that the large-scale vortex formation in the incompressible medium behind the blade system in the wind tunnel is a source of narrow-band acoustic radiation capable of exciting resonance self-oscillations in the tunnel channel. [ABSTRACT FROM AUTHOR]

The pneumatic conveying characteristics of chickpea (Cicer arietinum L.) of the variety Koçbasi were determined. The length, width, thickness, arithmetic mean diameter, geometric mean diameter, sphericity, volume, 1000 seed mass, bulk density, true density, porosity, projected area, terminal velocity, drag coefficient, pressure drop, power consumption, and seed damage, namely mechanical damage, germination test, and seed vigour index, were investigated experimentally. The positive low pressure system was used for the conveying of chickpeas. The power requirement and pressure drop were boosted with increasing the revolution of the blower and conveying capacity decreased with increasing pipe diameter. The highest pressure drop and power requirement were obtained for 54.5 mm pipe diameter, while the lowest pressure drop was found for 70.3 mm pipe diameter. The mechanical damage to the chickpeas for both pipe diameters increased as the revolution of the blower increased. [ABSTRACT FROM AUTHOR]

Abstract: The catastrophic failure of the main blower of a petroquimical plant boiler is discussed. The preliminary analysis of all the damage suffered by the machine indicated that the rotor was subject to strong unbalanced forces due to the breakage of one or more blades. Root Cause Analysis (RCA) was employed to determine the events responsible for failure. It could be established the bearing box nearest to the gearbox was damaged first, and the consequent displacement that was transmitted through the coupling, tore the gearbox out of its base. The reconstruction and analysis of the deformations of the analyzed parts allowed identifying the initiation of the fracture at the cone rotor. Manufacture defects contributed to the occurrence of the failure due to an excess rotating speed overload. [Copyright &y& Elsevier]

The ventilator, a life-saving device for COVID-19-infected patients, especially for pneumonia patients whose lungs are infected, has overwhelmingly skyrocketed since the pandemic of COVID-19 diseases started in December 2019. As a result, many biomedical engineers have rushed to design and construct emergency ventilators, using the Ambu-bag squeezing ventilator to compensate for the insufficient ventilators supply. The Ambu-bag squeezing ventilator, however, suffers from the limitation of delivered tidal volume to the patient, the setting respiration rate and the noisy operational sound due to the movement of mechanic parts. The Ambu-bag based ventilator is, hence, not suitable for prolonged treatment of the patient. This paper presents a design and construction of a blower-based pressure-controlled ventilator for home-treatment COVID-19 patients featured with our novel-designed flow and pressure sensor, electronic peep valve and proportional controlled valve. Our proposed ventilator can be programmed with the suitable parameter setting depending upon the weight, height, gender, and blood oxygen saturation (SpO2) of the patients. This is useful in the current situation of COVID-19 pandemics, where trained medical staff is limited. The designed ventilator is also equipped with a safety mechanism, including an excessive-pressure-release valve, excessive flow rate, overpressure, and over-temperature blower to prevent any hazardous event. A home ventilator server is also set where all ventilator parameters will be acquired and broadcasted for remote access of the health provider. The designed blower-based ventilator has been calibrated and evaluated with a lung simulator and standard ventilator tester, including alarmed functions, safety mechanism, sound level, and regulated pressure. The respiration output graph is complied with the simulation. The blower-based ventilator for home-treatment COVID-19 patients is suitable for life support, commensurate with the strict requirements of the FDA for life-support ventilators, and ready to be tested with animal subjects in the next phase. [ABSTRACT FROM AUTHOR]

Abstract: A polymer electrolyte membrane fuel cell (PEM FC) system as a power source used in mobile applications should be able to produce electric power continuously and dynamically to meet the demand of the driver by consuming the fuel, hydrogen. The hydrogen stored in the tank is supplied to the anode of the stack by a fuel delivery system (FDS) that is comprised of supply and recirculation lines controlled by different actuators. Design of such a system and its operation should take into account several aspects, particularly efficient fuel usage and safe operation of the stack. The exiting unconsumed hydrogen is circulated and reused to increase the efficiency and at the same time maintain the humidity in the anode side of the stack, thereby preventing drying and flooding in the channel which can affect the stack performance. A high pressure difference across a cell between the anode and cathode could cause damage on thin layers of the cell components and water imbalance in the membranes. In this paper, we analyze a hybrid fuel delivery system that consists of two supply and two recirculation lines. The major components were a pressure regulator, a flow control valve, an ejector, and a blower. These models were developed and connected in order to analyze dynamic behavior of the fuel delivery system. Based on the models, two control strategies, a decentralized classic proportional and integral control and a state feed-back control were designed and optimized to keep a constant pressure in the anode flow channel and a constant ratio of mass flow rates from recirculation to supply lines. The integrated system with the two different controllers was simulated to evaluate its tracking and rejection performance at different references and disturbances. [Copyright &y& Elsevier]

This 74-in-diameter blower had an overhung rotor design of titanium construction, operating at 50 pounds per square inch gauge in a critical chemical plant process. The shaft was supported by oil-film bearings and was direct-driven by a 3000-hp electric motor through a metal disk type of coupling. The operating speed was 1780 rpm. The blower shaft and motor shaft motion was monitored by Bently Nevada proximity probes and a Model 3100 monitoring system. Although the blowers showed very satisfactory vibration levels during test runs at the manufacturer's plant, the vibration levels in situ had always been higher than was desirable. After several months of monitoring showed ever increasing vibration levels, one of the blowers was shut down in order to diagnose and resolve the problem. Several steps were taken to diagnose the problem: (1) The rotor was removed and the shop balance was checked and corrected. (2) The bearing support movement due to thermal expansion was measured. Then the shafts were misaligned in the cold condition in order to achieve near-perfect shaft alignment during normal operation. (3) The expected shaft vibration at the bearings was determined using lateral rotor dynamics analysis, including critical speed mapping. (4) A heavy sleeve was added to the blower shaft to increase the radial load on the drive-end bearing. (5) The metal disk type of coupling was replaced by a gear coupling. (6) The finite element and impact of the bearing support pedestal were tested to determine the stiffness of the bearing support. (7) The shaft movement was measured during a coast-down. (8) Tilting-pad bearings were evaluated as a possible replacement for the original standard sleeve type of hydrodynamic oil-film bearings. The final solution showed the importance of coupling angular stiffness (often rarely considered in machine design), rotor dynamic analysis, and field alignment. [ABSTRACT FROM AUTHOR]

This study explores the impact of filtration on energy use in residences based on yearlong measurements in 19 homes in Toronto, Canada. Results show that permanent split capacitor (PSC) motor fans drew approximately 40% more power than electronically commutated motor (ECM) fans and the median efficacy (flow divided by power) of ECM fans was 43% higher than that of PSC motor fans. In response to a pressure drop of 150 Pa, ECM fans drew more power (46% − 58% increase) and generally tended to maintain airflow rate, while PSC motor fans drew less power (10% − 23% decrease), but generally tended to reduce airflow rate. Filter pressure drop was not strongly correlated with filter nominal efficiency; thus, the use of higher-efficiency filters may not impact fan power draw. Fan energy consequences of high-efficiency filters are negligible in our sample, and because HVAC runtimes were generally low (median = 11%), the difference between the energy consumption of ECM and PSC motor fans at typical runtimes was small (less than 10 kWh per month). Filters in systems with ECM fans have higher effectiveness per unit of power draw than those in systems with PSC motor fans. [ABSTRACT FROM AUTHOR]