Centrifugal Blower Research Articles

Development of a Versatile and Reversible Multi-Stack Solid Oxide Cell System towards Operation Strategies Optimization

Abstract In context of Temperature Electrolysis based on Solid Oxide Cell technology, CEA LITEN has developed a new investigation tool (MURPHY) devoted to the operation of several Solid Oxide stacks. MURPHY enables stack operation in both the electrolysis (SOE) and the fuel cell (SOFC) modes. For the later, H2, CH4, and natural gas can be used as fuel. A compact Balance of Plant (BOP) is designed to (i) provide air by centrifugal blower, (ii) target high thermal integration and performances, (iii) preheat inlet gases, (iv) recycle fuel exhaust, and (v) control pressure levels. Instrumentation was defined to support modeling development and accurate process efficiencies characterization. 
MURPHY is currently compatible with four stacks of CEA standard base design (25 cells, of 100 cm² active area), the corresponding maximum power range of the module is -16/4 kWDC for supply and venting of gases produced.
This report details system architecture. It also puts forward experimental results related in an environment controlled by thermal phenomena. Performance and efficiency curves obtained under parametric variations of temperature and flowrates are reported for both SOE and SOFC-H2 modes. A special attention is given to heat performance. In this view, flow parameters at several locations over circuitries are provide

Guideline for Large-Scale Analysis of Centrifugal Blower Using Wall-Resolved Large Eddy Simulation

Abstract To reduce the number of prototypes during product design and accurately predict unsteady phenomena occurring at off-design points, a method for accurately predicting the performance of centrifugal blowers through numerical analysis is required. This article presents a guideline for accurately predicting the performance of centrifugal blowers using compressible flow analysis with large eddy simulation (LES). In LES analysis, it is important to have a grid resolution that resolves the minimum vortex scale near the wall (referred to as wall-resolved LES) and to consider detailed geometry such as the length of the suction pipe. The calculations in this study used a model blower, which is a scale model of a single-stage centrifugal blower for use in industrial plants. The model blower was experimentally measured for various parameters such as the blower pressure coefficient, the static-pressure-rise coefficients of the impeller and vane-less diffuser, the shaft power, and the pressure fluctuations at the inlet of the impeller and the inlet of the vane-less diffuser. The results of these measurements were compared with those obtained from the wall-resolved LES. The study confirmed that the accuracy of performance prediction can be improved to less than a 4.0% error in the blower pressure coefficient at both design and off-design operating points by resolving the minimum vortex scale with 14.6 billion-grid elements and considering the detailed geometry.

On the enhancement of acceptable blockage of open jet wind tunnel by employing modifications based on concepts of boundary layer and jet flow for testing of aero-rotors

The conventional closed and open jet tunnels suffer from various adverse blockage effects that alter the flow conditions generating erroneous results when larger than allowable blockage models are tested. The maximum acceptable blockage is limited to 25 % for an open jet tunnel. The physics behind the inferior blockage capacity and their redressal is investigated. Hitherto, numerical models are developed to rectify the blockage troubles that introduce an additional complex case-based mathematical modeling to reckoning the results. In the current paper novel approach to redesigning the tunnel to solve blockage troubles is investigated that facilitates evading of mathematical techniques and securing accurate results straightforwardly. A hypothetical design incorporating the remedies is proposed, capable of conditioning the flow in a manner that debilitates the adverse effects of solid blockage, wake blockage, jet expansion, etc. The hypothesis is theoretically expounded by the boundary layer and jet flow phenomenon. The modified blower-type open jet wind tunnel constitutes a centrifugal blower, long inlet duct, plenum chamber around the test section, and collector. The modified wind tunnel is tested through experiments executed on four different-sized Savonius rotors creating 10 %, 30 %, 50 %, and 60 % blockage. The static pressure along the contours of the blades of rotors is obtained. The experimental results are juxtaposed with CFD results carried out at free-wind boundary conditions and standard classic experimental results performed in conventional wind tunnel at 11 % blockage. A blockage enhancement of 25 % is achieved by the approach of modification in the design of a conventional open jet wind tunnel.

A novel fault early warning method for centrifugal blowers based on stacked denoising autoencoder and transfer learning

Centrifugal blowers are easy to get faults due to the harsh working environment, and appropriate fault early warning is of great significance for predictive maintenance. Traditional fault early warning methods have poor resistance and feature learning ability in dealing with multivariate data with noise, and cannot achieve domain adaptation in different working environments. Aimed at solving these problems, this paper proposes a novel fault early warning method for centrifugal blowers based on stacked denoising autoencoder with sliding window (SW-SDAE) and transfer learning. The developed SW-SDAE model can effectively learn representative degradation features and temporal dependence from multivariate time-series data with noise. The reconstruction errors of SW-SDAE are used to construct the health indicators, which accurately characterizes the health status of the centrifugal blower. Meanwhile, transfer learning is employed to solve the problem of domain adaptation for different working environments. The established source domain warning model is successfully transferred to the target domain by minimizing the maximum mean discrepancy. When the health indicator exceeds the warning threshold, a fault early warning is performed. Experimental results demonstrate that the developed SW-SDAE warning model integrating transfer learning significantly resists the interference of noise and improves the domain adaptability for different working conditions. The proposed method achieves fault early warning 5.67 h without false alarms before failure and shows superior warning performance compared with traditional warning methods.

Experimental study of parchment coffee drying using the combined fluidization and microwave process: Analysis of drying curves and thermal imaging

In this study, several experimental drying conditions for parchment coffee were investigated using microwave-assisted fluidization. The experiments were carried out in a prototype equipment consisting of a multimode microwave equipment (700 W and 2.45 GHz frequency) with a drying chamber inside of the cavity. Fluidization was provided by a centrifugal blower (1500 rpm nominal) operating at different controlled speeds. The experimental design corresponded to three microwave power levels (0, 210 and 350 W) and different air speeds (0, 1.7 and 3.4 m/s) at 25 and 40 °C. The experimental moisture evolution and temperature distribution showed that fluidization homogenizes the temperature profiles. Thermographic images further indicated that intermediate microwave power levels (210 W) achieved high uniformity in surface temperature distribution. The combination of fluidization and microwaves facilitated a significant acceleration of the drying rate without exceeding temperature limits, thus preventing any adverse effects on the final product's quality.

Analysis of numerical modeling of steady-state modes of methane–hydrogen mixture transportation through a compressor station to reduce CO2 emissions

This study presents a mathematical model to evaluate the performance of gas pipelines during hydrogen injection in a gas pipeline-compressor station. The developed model presents the calculation of methane–hydrogen mixture (CH4/H2) transportation through the compressor station, where the compensation of pressure drops in the mass and energy balance takes place. Simultaneously, in the operation of the centrifugal blower system of gas compressor stations, the emissions of CO2 are considered, considering the mixing of gas media and the compression of CH4/H2. This mathematical model is realized for the pipeline transportation of hydrogen, at which the principle of mixture expansion occurs. The aim is to solve the problem of CO2 emissions at compressor stations. The optimization procedure has been formulated using a system of nonlinear algebraic equalities. The research focuses on the adaptation of existing gas transportation systems to CH4/H2 transportation and the impact of environmental risks on the operation of compressor station equipment. In this case, it is possible to determine the quantitative amount of hydrogen that can be added to natural gas. By solving the problem of finding the inner point of sets using the system of nonlinear algebraic equalities, it is possible to obtain the control parameters for safety control of technological modes of CH4/H2 mixture transportation. The study findings reveal that the consumption of gas charger and hydrogen was 50.67 and 0.184 kg/s, respectively, and the estimated efficiency resulting from the modified turbine design was 75.1 percent. These results indicate that the equipment operates more efficiently when hydrogen is being transported. The numerical analytical results indicated in this study hold practical significance for design applications. It will assist in identifying and evaluating the restrictions that may develop during the technological, operational, and design stages of decision-making.

Development of a Versatile and Reversible Multi-Stack Solid Oxide Cell System Towards Operation Strategies Optimization

High Temperature Electrolysis based on Solid Oxide Cell technology is rapidly entering an industrialization phase, driven by promises of high efficiencies compared to the more market-ready solutions. To decrease the CAPEX and footprint related to module-based scale-up strategies, multiple stacks are typically assembled within the same thermal enclosure. As such, thermal phenomena become much more prominent in determining stack behavior compared to single stack test benches, and appropriate control strategies have to be developed.In this context, CEA LITEN has developed a new investigation tool (MURPHY) devoted to the operation of several Solid Oxide stacks within the same thermal enclosure. MURPHY enables stack operation in both the steam electrolysis (SOE) and the fuel cell (SOFC-H2) modes. For the later, CH4, natural gas or NH3 can be used as fuel, while additional gases are being considered. The one module system incorporates a compact Balance of Plant (BOP) located closely to the thermal enclosure. Its main functions are (i) to provide inlet process air by centrifugal blower towards higher efficiency, (ii) target high level of overall thermal integration and performances, (iii) actively preheat inlet gases independently of overall furnace temperature, (iv) recycle hot/cold fuel exhaust, and (v) control pressure levels distribution through multiple back-pressure valves. Overall, a high level of instrumentation was deployed to support modeling development and estimate accurate process efficiencies.MURPHY is currently compatible with four stacks of CEA standard base design [1]. Each comprising 25 cathode-supported cells each of 100 cm² active area, the corresponding maximum power range of the module is -16/4 kWDC [2], [3]. Nevertheless, the Hot Box has some capacity to adapt to different stack geometries and partner’s need. Finally, the MURPHY system is connected to the Multistack platform [4] for supply and venting of gases produced.This report details system architecture down to component level. It also puts forward preliminary experimental results related to stack operation in an environment controlled by thermal phenomena. Performance and efficiency curves obtained under parametric variations of operating conditions (Temperature, flowrates) are reported for both SOE and SOFC-H2 modes. A special attention is given to heat performance of the overall system and its components. In this view, flow parameters (composition, temperature, pressure) at several locations over the reactant circuitries are provided.[1] G. Cubizolles, J. Mougin, S. Di Iorio, P. Hanoux, and S. Pylypko, “Stack Optimization and Testing for its Integration in a rSOC-Based Renewable Energy Storage System,” ECS Trans., vol. 103, no. 1, pp. 351–361, Jul. 2021, doi: 10.1149/10301.0351ecst.[2] J. Aicart, S. Di Iorio, M. Petitjean, P. Giroud, G. Palcoux, and J. Mougin, “Transition Cycles during Operation of a Reversible Solid Oxide Electrolyzer/Fuel Cell (rSOC) System,” Fuel Cells, vol. 19, no. 4, pp. 381–388, May 2019, doi: 10.1002/fuce.201800183.[3] J. Aicart et al., “Benchmark Study of Performances and Durability between Different Stack Technologies for High Temperature Electrolysis,” in 15th European SOFC & SOE Forum, Lucerne, Switzerland, May 2022, vol. A0804, pp. 138–149.[4] J. Aicart et al., “Performance evaluation of a 4-stack solid oxide module in electrolysis mode,” Int. J. Hydrog. Energy, vol. 47, no. 6, pp. 3568–3579, Jan. 2022, doi: 10.1016/j.ijhydene.2021.11.056. Figure 1

Experimental Investigation on Incorporation of Zinc-Ferrite Nanocoated Baffles for Improving the Performance of Field Power Electrical Transformer Integrated with a Solar Air Heater

Solar energy is the most accessible, eco-friendly, and renewable energy source available to meet the world’s expanding energy needs. Solar collectors are commonly utilized to convert solar energy directly into heat for purposes ranging from house heating to timber seasoning and crop drying. The purpose of this research is to design a modified solar air heater (SAH) with a baffle plate and to examine the performance due to the provision of zinc-ferrite nanocoated baffles. The entire system is mounted over a transformer for effective cooling and also produces hot air for industrial requirements. A flat plate collector and a centrifugal blower were used in the experiment. Maximum output air temperatures of 55°C, 62°C, and 72°C were measured for collectors without baffles, baffled collectors, and inverted baffled collectors, respectively. It was also found that the thermal efficiency of flat plate collectors without baffles was 36%, with baffles, it was 44%, and with inverted baffles it was 54%. This study shows that inverted SAH with zinc-ferrite nanocoated baffle plates works better than SAH without baffle plates or with baffle plates in the normal position.

Spatiotemporal Characteristics and Pressure Fluctuations of Internal Flow in a High-Speed Centrifugal Blower for Vacuum Cleaner at Low Flow-Rate Conditions

The steady and unsteady characteristics of the internal flow in a high-speed centrifugal blower are studied by computational fluid dynamics (CFD) approach at low flow rates. It is demonstrated that as the flow rate decreases, the separation of flow in the blade passage becomes serious, and separated vortexes always occur on the suction surface of the blade which gradually expand and block the passage. The stall cells move downstream and generate vortices at the exit of the passage, resulting serious loss to the performance of the blower. Q-criteria is used to analyze the flow field and explore the evolution of the vortex structure in the impeller. It is further found that strong pressure fluctuations are caused by the rotating stall in the impeller. At the stall conditions, the instability characteristics are particularly obvious. At flow rates of 0.65Qn and 0.47Qn, the pressure fluctuation in the blade passage is dominated by the blade passing frequency, while a lower frequency dominates at 0.26Qn. Moreover, the flow on the suction surface of impeller blades fluctuates substantially. The characteristics of steady flow and unsteady flow can clearly explain the internal flow of centrifugal blower for vacuum cleaners at low-flow conditions, which can be widely used in various engineering designs of vacuum cleaners.

Modifikasi Sudu-sudu Blower Sentrifugal yang Diaplikasikan pada Turbin Pico Hydro

The water turbine must be specially designed according to the calculation of its energy potential, proportional to the height of the falling water and the discharge. This research is conducted to study the solution fluid engine that functions as a pico hydro water turbine, namely a centrifugal blower with a simple construction, operating at low head, small discharge, easy installation and operation and low price. The blower used in this test is a blower that is already on the market with an impeller diameter of 15 cm, inlet size of 2 inches. The test was carried out at a constant head (falling water height) of 5 m. The working principle of the blower is reversed, that is, water from a certain height flows through the rapid pipe and enters the exhaust side of the blower until the water moves the blower and exits through the blower inlet to the draftube. The purpose of this study was to determine the effect of modification of the blades on the increase in efficiency of the picohydro turbine. This study uses an analytical method with testing parameters based on calculating the value of water discharge, water power, torque, turbine mechanical power and turbine efficiency. To increase the power and efficiency of the blower as a turbine, modifications are made to the blower blades. With the modification of the blower blades, the turbine efficiency increases by 10 percents from before the modification.

Research on Centrifugal Blower Design and Optimization Method Based on Mean Camber Line Optimization and CFD

In recent years, with the development of domestic industry and the progress of production technology, the centrifugal blower, as a piece of nuclear equipment in the industry, needs to be upgraded and optimized to improve its performance. Thus, based on the mean camber line optimization and CFD, this paper carries out the design and aerodynamic optimization for a centrifugal blower, and a corresponding 3D aerodynamic optimization platform is built. Then the effects the mean camber lines have on the aerodynamic performance of the centrifugal blower are further analyzed. The results show that the stall margin and efficiency of the centrifugal blower are improved, going up to nearly 8.5% and 1.5%, respectively, after the optimization, while the total pressure ratio basically remains unchanged. The optimized mean camber lines can control the Mach number and restrain the separating flow more effectively, which contributes to improving the carrying capacity of the blower and verifies the advancement of the optimized platform. This provides a novel method for the design and optimization of centrifugal blowers.

Design of a Compact Dry Cooler With an Aluminum Heat Exchanger Core for a Supercritical CO2 Power Cycle Is Evaluated for a Concentrating Solar Power Application

Abstract As the supercritical CO2 power cycle develops and the component technologies mature, there is still a need to reduce the associated capital and operating costs to maintain a competitive levelized cost of electricity (LCOE) in order to enter the market. When considering concentrating solar power (CSP) coupled with an sCO2 power block and sensible thermal storage, the technology presents a clean source for utility-scale power generation to support baseload or peak-load electrical demand. However, the LCOE of the technology is still considered higher than the competing technologies and should be reduced to better compete in the market; 2030 targets for dispatchable solar plants are 5¢/kWh for baseload CSP and 10¢/kWh for peaker plants, as set by the United States Department of Energy. In response to this need, this study is targeting improvements in the power cycle precooler to reduce power block contribution to LCOE. This study considers a dry cooler, as CSP plants are sensitive to water consumption because many installations are slated for remote or arid locations where solar irradiance is very high, but water is scarce. Furthermore, the power block footprint for an sCO2 system is quite compact, especially as compared to a steam cycle. Therefore, there is interest in installing a more compact dry cooler that is proportional to the reduced footprint sCO2 power block, while conventional dry coolers are an order of magnitude larger. The competing goals of size, performance, and cost were considered in this study to develop a compact dry cooler that can easily be packaged with the power block, significantly reducing the installation and transport cost compared to the current state of the art, while maintaining or improving upon the heat transfer performance and impact on plant LCOE. This paper details the high-level findings of a large dry cooler sensitivity study for design point selection, design of the compact dry cooler, expected year-round performance for the dry cooler and the power cycle, and the predicted LCOE for a 30-year plant life. It was found that an aluminum heat exchanger core can be suitably designed to meet the pressure and temperature requirements for a precooler in an sCO2 recompression Brayton cycle. The dry cooler assembly was found to have improved heat transfer performance, allowing for increased cycle efficiencies and a reduced plant LCOE. When coupled with a centrifugal blower and compact transition duct, the dry cooler assembly was able to reduce the installation footprint by over 50%.

Design Methodology and Concept Demonstration of Preassembled Additively Manufactured Turbomachinery Systems: Case Study of Turbocharger Based Medical Ventilators

Abstract The present research focuses on analyzing the feasibility of manufacturing complex turbomachinery geometries in a pre-assembled manner through an uninterrupted additive manufacturing process, absent of internal support structures, or postprocessing. In the context of the present COVID-19 pandemic, the concept is illustrated by a three-dimensional (3D)-printable turbine-driven blower-type medical ventilator, which solely relies on availability of high-pressure oxygen supply and a conventional plastic-printer. Forming a fully pre-assembled turbomachine in its final form, the architecture consists of two concentric parts, a static casing with an embedded hydrostatic bearing surrounding a rotating monolithic shell structure that includes a radial turbine mechanically driving a centrifugal blower, which in turn supplies the oxygen enriched air to the lungs of the patient. Although the component level turbomachinery design of the described architecture relies on well-established guidelines and computational fluid dynamics methods, this approach has the capability to shift the focus of additive manufacturing methods to design for pre-assembled turbomachinery systems. Upon finalizing the topology, the geometry is manufactured from polyethylene terephthalate (PETG) plastic using a simple tabletop extrusion-based machine and its performance is evaluated in a test facility. The findings of the experimental campaign are reported in terms of flow and loading coefficients and are compared with simulation results. A good agreement is observed between the two data sets, thereby fully corroborating the applied design approach and the viability of additively manufactured pre-assembled turbomachines. Eliminating long and costly processes due to presence of numerous parts, different manufacturing methods, logistics of various subcontractors, and complex assembly procedures, the proposed concept has the potential to reduce the cost of a turbomachine to capital equipment depreciation and raw material.

Prediction of Outlet Pressure for the Sulfur Dioxide Blower Based on Conv1D-BiGRU Model and Genetic Algorithm.

The sulfur dioxide blower is a centrifugal blower that transports various gases in the process of acid production with flue gas. Accurate prediction of the outlet pressure of the sulfur dioxide blower is quite significant for the process of acid production with flue gas. Due to the internal structure of the sulfur dioxide blower being complex, its mechanism model is difficult to establish. A novel method combining one-dimensional convolution (Conv1D) and bidirectional gated recurrent unit (BiGRU) is proposed for short-term prediction of the outlet pressure of sulfur dioxide blower. Considering the external factors such as inlet pressure and inlet flow rate of the blower, the proposed method first uses Conv1D to extract periodic and local correlation features of these external factors and the blower's outlet pressure data. Then, BiGRU is used to overcome the complexity and nonlinearity in prediction. More importantly, genetic algorithm (GA) is used to optimize the important hyperparameters of the model. Experimental results show that the combined model of Conv1D and BiGRU optimized by GA can predict the outlet pressure of sulfur dioxide blower accurately in the short term, in which the root mean square error (RMSE) is 0.504, the mean absolute error (MAE) is 0.406, and R-square (R2) is 0.993. Also, the proposed method is superior to LSTM, GRU, BiLSTM, BiGRU, and Conv1D-BiLSTM.

MESIN PENGERING GABAH MODEL BAK MENGGUNAKAN BAHAN BAKAR LPG

Conventional drying relies on sunlight has a number of drawbacks. In terms of productivity, drying takes a long time, for example: two until three days for sunny day or four to five days for cloudy weather. Design of a combined gas-fueled rice drying machine (Liquefied Petroleum Gas) as an alternative in drying rice does not depend on weather conditions, in both rainy and dry season. This drying machine uses a hot air distribute in pipe that have functions to remove water evaporation from the dried materials. The circulation of hot air in the room is very important to produce drainage in the drying chamber. Heat circulation in the drying chamber can take place naturally or forcibly using a fan into the extruder tube. Centrifugal blower has functions to suck or dispose hot air in a room. Heater drum of dry air functions as a drying device where hot steam is placed into the drum. The furnace has functions as a device for heating. From this study it can be concluded that the humidity in the drying chamber is 0.1875 kg water/kg air, the mass of drying air is 26.4915 kg, the requirement of fuel during the drying process is 3 kg of fuel, the time required for drying is 5.1623 - 11.6023 hours, the drying temperature of rice is 40oC, 45oC, and 50oC. The thickness of rice pile are 100 mm and 200 mm, mass of dried rice 50 kg and 100 kg, and efficiency of rice drying is 52.67% - 58.41%.

Automatically Controlled Dust Generation System Using Arduino.

A dust generator was developed to disperse and maintain a desired concentration of airborne dust in a controlled environment chamber to study poultry physiological response to sustained elevated levels of particulate matter. The goal was to maintain an indicated PM10 concentration of 50 µg/m3 of airborne dust in a 3.7 m × 4.3 m × 2.4 m (12 ft × 14 ft × 8 ft) controlled environment chamber. The chamber had a 1.5 m3/s (3200 cfm) filtered recirculation air handling system that regulated indoor temperature levels and a 0.06 m3/s (130 cfm) exhaust fan that exchanged indoor air for fresh outdoor air. Dry powdered red oak wood dust that passed through an 80-mesh screen cloth was used for the experiment. The dust generator metered dust from a rectangular feed hopper with a flat bottom belt to a 0.02 m3/s (46 cfm) centrifugal blower. A vibratory motor attached to the hopper ran only when the belt was operated to prevent bridging of powdered materials and to provide an even material feed rate. A laser particle counter was used to measure the concentration of airborne dust and provided feedback to an Arduino-based control system that operated the dust generator. The dust generator was operated using a duty cycle of one second on for every five seconds off to allow time for dispersed dust to mix with chamber air and reach the laser particle counter. The control system maintained an airborne PM10 dust concentration of 54.92 ± 6.42 µg/m3 in the controlled environment chamber during six weeks of continuous operation using red oak wood dust. An advantage of the automatically controlled dust generator was that it continued to operate to reach the setpoint concentration in response to changes in material flow due to humidity, partial blockages, and non-uniform composition of the material being dispersed. Challenges included dust being trapped by the recirculation filter and the exhaust fan removing airborne dust from the environmental chamber.

High-speed PMSM thermal analysis of totally enclosed fan cooled axial ventilation for centrifugal blower application

A temperature rise occurs when an electrical machine is fully loaded. The winding insulations of high-speed permanent magnet synchronous machines (PMSMs) are the most temperature-sensitive components, which can impact the machine’s longevity. Thus, recently, prediction for high-speed PMSM winding temperature has been given more and more attention. Thermal analysis by numerical (computational fluid dynamics (CFD) and finite element method (FEM)) and analytical lumped parameter thermal network (LPTN) methods have been widely used to estimate the temperature of totally enclosed fan cooled axial ventilation system (TEFCAVS) machines. Although numerical methods have more accuracy, their computation wastes time. Therefore, LPTN is being utilized in this paper due to the fastness of its computation. Firstly, estimated losses of high-speed PMSM with TEFCAVS via electromagnetic analysis, including copper, iron, permanent magnet (PM) eddy current, sleeve eddy current, and mechanical, are coupled to the LPTN model, which acts as heat sources for temperature prediction. Moreover, analysis shows that slot windings’ maximum temperature exceeds the winding insulation class with initial cooling configuration. Secondly, in order to mitigate slot winding temperature, the sensitivity study for liner conductivity, air gap’s heat transfer and lamination to housing’s contact is conducted by LPTN to identify which thermal parameter has more influence on mitigating the maximum temperature of the slot winding. Investigation shows that improving an air gap’s heat transfer has more influence than other parameters for mitigating slot winding maximum temperature below its insulation class. Lastly, the machine is designed and tested with the best thermal-sensitive parameters. Then test results for the maximum temperature of the winding are compared with estimated results to ensure the proposed LPTN correctness, and the calibration process confirms LPTN accuracy.

Electromagnetic and Thermal Analysis of 225 kW High-Speed PMSM for Centrifugal Blower Applications

In order to make centrifugal blowers environmentally friendly, machines with a lighter weight and a more compact size are required. Thus, the axial length of the machine needs to be minimized within the diameter limit. However, in the design methodology, losses and thermal study become very significant; thus, losses increase significantly to achieve the desired output power when the volume is excessively reduced. Moreover, due to the machine’s compact size, heat is concentrated rapidly without adequate cooling. It might lead to a temperature rise of the critical part of the machine above the safe limit, such as winding, thereby affecting its lifespan. This study considers the 225 kW high-speed permanent magnet synchronous machine (HSPMSM) with the forced air cooling axial ventilation system (FACAVS) used in centrifugal blower applications. Firstly, four different analytical models (A2–A5) in the electromagnetic analysis are derived by minimizing the initial machine’s (A1) axial length to achieve a lighter weight and more compact size with better electromagnetic performance. The best among analytical models is chosen as the A4 model with a lighter weight and a more compact structure in addition to higher torque density than A1, A2, and A3 models, and higher efficiency than A1, A2, A3, and A5 models by HSPMSM’s, optimal geometric design, and optimal material choice, respectively. Secondly, LPTN is designed to predict the entire analytical model’s thermal behavior in the thermal analysis. Investigation shows that winding temperature rises from the A4 model is maintained below winding insulation by the determined optimal axial ventilation parameters from the sensitivity analysis. Finally, different analytical models are prototyped and tested. The comparisons between predicted electromagnetic performance, winding temperature rise, and test results were carried out, and the results were found to agree with each other consistently.

Adaptive surge detection of magnetic suspension centrifugal blower based on rotor radial displacement signal and SOGI-FLL with prefilter

For the surge detection problem of high-speed magnetic suspension centrifugal blower, a second order generalized integral-frequency locked loop with prefilter (SOGI-FLL-WPF) is used for surge detection. This method is utilized to normalize the amplitude and frequency of the surge signal by using the rotor radial displacement signal in the magnetic suspension blower. So that the response speed of detecting surge signal is not affected by the frequency and amplitude, and the frequency of the blower surge vibration signal is tracked adaptively. As a result, the fast response ability of the surge signal detection is improved. Specifically, firstly, the rotor radial displacement signal is collected in real time. And then, the rotor speed is identified by SOGI-FLL, and the identified speed information is input to SOGI for notch. Finally, the surge detection is carried out by SOGI-FLL-WPF for the signal after notch. The 105 kW magnetic suspension centrifugal blower is applied for the surge detection experiment. The experimental results show that the surge detection method based on rotor radial displacement signal and SOGI-FLL-WPF can detect the surge signal immediately after its occurrence. The proposed detection method needs no additional detection unit, and has the advantages of simple algorithm, fast response speed and small amount of calculation. In addition, it can effectively reflect the change of frequency in the process of surge.

Numerical study of aerodynamic performance and flow characteristics of a centrifugal blower

PurposeThis paper aims to focus on the effect of the operating condition such as the impeller speed on the centrifugal fan performance and flow characteristics. The ability to predict the behavior of the airflow motion in a centrifugal blower is essential for obtaining the topology optimization design.Design/methodology/approachA physical model of the air blower consisting of these main parts in a blower system: collector, impeller, outlet flange and volute casing, and the appropriate boundary conditions are set up by ANSYS software. Computation fluid dynamics are performed for the numerical analysis. The calculation of blower performance parameters such as total pressure, efficiency and flow rate is based on the Reynolds averaged Navier–Stokes equations and k-turbulence flow model.FindingsThe numerical results show that the change in operating conditions has a significant effect on the blower performance, and the pressure maintained inside the blower is higher for a larger impeller rotational speed.Originality/valueThis work is original and has not yet been submitted to elsewhere or published previously.