Centrifugal Blower Research Articles

Compressible LES Analysis of Unsteady Pressure Fluctuation in Centrifugal Blower

Large Eddy Simulation (LES) for compressible flow was conducted to analyze the pressure fluctuation at 17% of the impeller rotation frequency, which was confirmed at the impeller inlet and diffuser inlet under the operation condition on the lower flow rate in centrifugal blower with peripheral Mach number of 0.48. It was found that the pressure field in the diffuser generally decreases when the region of large radial flow caused by the diffuser rotating stall passes through the scroll tongue. As the pressure decrease in the diffuser, the pressure upstream of the impeller also decrease.

Experimental and numerical studies of one-directional and bi-directional flow conditions across tube banks heat exchanger

Bi-directional flow condition imposes different fluid dynamics and temperature changes compared to that of the usual one-directional flow condition. Bi-directional flow can be found in applications like thermoacoustic systems that offer a green technology for at least two major applications: refrigeration and power production. The technology is appealing as an alternative to traditional systems as it offers the replacement for the use of harmful working media and exhausted resources with the use of inert gaseous with relatively fewer moving mechanisms. As the fluid dynamics and heat transfer of bi-directional flow in a thermoacoustic working environment is less known, it is difficult to estimate losses and gain, especially during the design stage. This paper reveals the differences to be expected in the behaviour of flow and heat transfer through experimental as well as Computational Fluid Dynamics (CFD) results of one-directional and bi-directional flow conditions. Two different drivers were used to create the two different flow conditions: a loudspeaker for the bi-directional flow and a centrifugal blower for the one-directional flow. Both conditions were monitored based on flow amplitude that is calibrated between the two drivers. Results of velocity, temperature and, vorticity are recorded for Reynolds number that ranges between 270 and 1700. Analyses are supplemented with data from validated two-dimensional computational fluid dynamics models that were solved using the Shear-Stress-Transport (SST) k-ω turbulence model with second-order accuracy for all equations. Interesting features of differences in temperature and velocity changes between the one-directional and the bi-directional flows are reported. The temperature and velocity at upstream and downstream locations of the tube banks heat exchanger are almost the same for bi-directional cases but are significantly different when a one-directional flow is flowing over the heated tubes. In addition, the interplay between natural and forced convections is seen to affect the results that were recorded for the two flow conditions. The presence of thermally developing and fully developed regions is also discussed. The results indicate that the heat transfer behaviour of bi-directional flow is not the same as in the one-directional flow and the future calculation for heat transfer for bi-directional flow conditions of thermoacoustic must be carefully done with consideration of changes of flow conditions between the one-directional and the bi-directional flow conditions so that error could be minimized in the evaluation of the system’s performance.

Design and Fabrication of Centrifugal Blower using Locally Sourced Materials

This paper deals with the design and fabrication of a centrifugal blower. A backwards-curved blower was employed in the study, because the backwards-inclined blower is highly efficient, operates at approximately twice the speed of a forward-curved air blower, and is suitable for high-state pressure applications. The design consideration and analysis concerned within this study is for a single-stage centrifugal blower with capacity, Q (0.317m3/min) at a pressure, P (10,000Pa), head, H (61.87m), and shaft speed, N (1450rpm). The lowest air volumetric rate of 0.073 m3s-1 was obtained at closing the inlet (85%), the impeller speed (400rpm), and the air volumetric rate (0m3s-1) at closing the inlet (100%) for all the impeller speeds. The highest air volumetric (0.379m3s-1) was obtained at closing the inlet (0%) and impeller speed (960rpm). The impeller speed of 400rpm with a static pressure value of 47.03Pa, can be computed as the pressure value at 960rpm (i.e., 40.07Pa), indicating a 17% deviation (difference of 6.96 Pa). The highest total efficiency achieved is on closing the inlet of 50% and the impeller speed of 960rpm was attained at about 9.93%, whereas the lowest total efficiency on all the impeller speeds is achieved at the closing inlet of 0%. The result shows that the centrifugal blower was efficient over a wide range of flows. The blower provides a small unit of footprints with a good turn-down capacity.

Development of a Corn Drying System

Corn as a staple farm produce are usually harvested at a point or time when the moisture content is more than 25% (wet.basis).,and therefore, it is easily attacked by fungi and other diseases causing organism and even physical damage, thereby reducing the market value of the crop. Drying must be carried out on those products to prevent deterioration. The objectives of this research are to develop a device that can reduce the moisture content of corn using electronic components and equally carryout evaluation on the device. Shelled corns with initial moisture content of between 25-30% (w.b.) is the major material used in this research work. A Heating element incorporated in the device supplied the needed heat which was delivered to the drying chamber by the help of a centrifugal blower. The drying experiment was carried out at three different temperature thus; 45 oC, 55 oC and 65oC. The moisture content at this varying temperature was used to determine the drying rate and the drying efficiency. The results showed clearly that the dryer air temperature affect the drying rate, the efficiency of drying, and the quality of the material. It is equally clear that the best drying rate and temperature is 65oC average 4,95% / hour, high efficient at drying temperature 55oC and 65oC equal to 86,27% and 83,51%, and best material quality with dryer temperature 55oC.

A novel fault diagnosis method based on multi-level information fusion and hierarchical adaptive convolutional neural networks for centrifugal blowers

Multi-sensor data fusion can provide abundant and complementary fault information. To improve the accuracy and robustness of diagnosis, this paper proposes a novel fault diagnosis method for centrifugal blowers based on multi-level information fusion and hierarchical adaptive convolutional neural network (HACNN). Multi-level information fusion integrates temporal information, feature extraction, feature selection into data fusion. This fusion strategy can acquire comprehensive and representative fault information from multi-sensor signals. The constructed HACNN greatly enhances the feature learning ability of the network and avoids unnecessary computational consumption by adaptive expansion. The effectiveness of the proposed method is evaluated by using datasets from a centrifugal blower test rig. The experimental results show that the testing accuracy and F1-score of the proposed method reach to 98.18%, which is obviously higher than that of CNN, DNN, DBN, BPNN and SVM in corresponding fusion method. It proves that the proposed method has superior diagnosis performance.

Influence of deposits on rotor impellers of a centrifugal blower of a gas-pumping unit on static imbalance

Compressor station equipment undergoes a sensitive adjustment process before commissioning. One of its most important tasks is balancing the blower rotor, as a result of which the forces acting in the system are balanced. Unbalance is the imbalance of the rotor, leading to the occurrence of forces and moments that cause vibration, both of the rotor itself and of the entire machine as a whole. Currently, there is no absolutely effective method for gas purification, which negatively affects the flow path of the equipment. This is especially true for gas pumping units that compress associated petroleum gas, as well as for GPUs operating in underground gas storage facilities and used in cases where the pressure of the sampled gas is lower than the pressure in the pipeline and must be raised. All this contributes to the emergence of an imbalance in the system. The work mathematically simulates the effect of deposits on the static balance of the rotor of a centrifugal blower.

Design, Fabrication and Performance Evaluation of Groundnut Dehulling and Separating Machine

The process of oil extraction can be enhanced by dehulling, oil produced from groundnut seeds serve as a good source of protein, vitamin, fat, oil, and crude fibers. A groundnut dehulling machine was developed, having two dehulling rollers, rubber beaters, screen, blower unit, seed and chaff outlet. The separator unit has a centrifugal blower, screen and collecting tray. It’s powered by 3 hp electric motor, which transmits constant speed of 3636 rpm to the blower and 1000 rpm to rubber beaters. Groundnut used was at 7.32% moisture content (w.b). Dehulling was achieved through the compression and shearing action of the rotating dehulling roller against the stationary dehulling roller. The effect of dehulling roller clearance (6.5 mm,7.0 mm, 7.35 mm and 7.5 mm) and speed (700 rpm and 750 rpm) was evaluated on dehulling efficiency, machine capacity, mechanical damage and separation efficiency. The result obtained after testing the machine shows that 7.35 mm clearance and 700 rpm of the dehulling roller gave optimum average dehulling efficiency 95.80%, separation efficiency 81.40% and the least mechanical damage 11.01%. Machine capacity of 97.98 kg h-1. was obtained at 750 rpm and 7 mm dehulling roller clearance. The results obtained during evaluation was statistically analyzed, multiple linear model equations which are capable of predicting the effect of dehulling roller clearance and speed on dehulling efficiency, machine capacity, mechanical damage and separation efficiency was developed.

Upgrading Air Distribution System in the Thermal Units for Fish and Meat Products Aiming at Improving Efficiency of Heat-exchange Processes

The issue of the equivalence of the physical parameters of the working medium in the heat-treatment zone of fish and meat products is solved by organizing uniform high-speed fields of the working medium in the working area, which is ensured by the corresponding design. The aerodynamic characteristics of a double-sided centrifugal blower fan with a vertical arrangement of the drive shaft and a spiral scroll with two outlet openings, the outlines of which were carried out according to the design square rule, provided that the opening and width of each outlet was equal to the half-opening and half-width of the outlet of the spiral case of the industrial prototype, were investigated. When testing the aerodynamic characteristics of a double-sided blower, the identities of the full and dynamic air pressure developed by the fan at all points of the measured cross-section of each of the two oppositely directed outlet pipes are established to be identical, which indicates the equalization of air flows. In this case, the dimensionless ratio of the cross-sectional areas of the equistatic pressure duct to the initial pressure is 0.20, and the cross-sectional area for the air passage of the heat exchanger, conditionally being the perforated base of the duct, was 0.0978 m2 . The test results confirmed the reliability of analytical calculations and the feasibility of using these fans, which reduces energy consumption, a specific quantity of metal, and the cost of equipment in general.

Development of a Laminar Air Flow System for Preventing Surgical Equipment Table Infections

Nowadays, the infections cause the higher patient mortality and longer time in hospitals and clinical treatment units. It requires the good quality of healthcare services. This paper presents the research in an attempt to realize a mobile laminar airflow system for preventing the contamination of airborne pathogens by protecting the surgical site area as well as the instrument table as low-cost as possible. The portable laminar airflow system and centrifugal fan are modeled by using computer-aided design (CAD) software. This system concludes a blower, UVC lamp, standard filter, high-efficiency particulate air (HEPA) filter, and instrument table. Then, the proposed device was verified through numerical simulations. Computational Fluid Dynamics (CFD) was performed to optimize the system design by examining and evaluating the results, as well as computing the aerodynamic characteristics for the system's centrifugal blower and taking fan pressure variation into account while adjusting inlet flow. As a result, sterile conditions may be created instantaneously and anyplace using this proposed laminar airflow system. The innovative layered airflow sterilizer may achieve a local Biosafety Level II in a specific area, such as an isolation room, patient bedroom, or operating room. After modeling the system, the finer mesh of centrifugal fan was carried out to ensure the accuracy of numerical simulation. There are four domains discretized in a centrifugal fan such as impeller fluid domain, volute fluid domain, inlet, and outlet fluid domain. The inlet mass flow rate strongly affects the performance of the centrifugal fan. The numerical results show that the total pressure maintained inside the blower increase as the flow rate gets larger. The results of this study provide an essential basis for optimizing system design in future investigations.

Ways to reduce hydraulic losses in multistage centrifugal pumping equipment for mining and oil-producing industries

Purpose. To study hydraulic losses in pumping units during pumping and transportation of liquids, to develop the design and technology solutions to improve the energy efficiency of centrifugal pumps in the mining and oil-producing industries. Methodology. In the theoretical and experimental analysis of hydraulic losses during the transportation of liquids, the hydraulics and experimental analysis methods were used. Findings. As a result of the research carried out, a new design scheme of a multistage centrifugal pump has been developed, providing a coaxial arrangement of impellers, which allows reducing hydraulic losses in pump elements and increasing the energy efficiency of pumping units. Originality. Based on the analysis of existing designs of multistage blowers of axial and centrifugal types, the distribution of hydraulic losses in the elements of a centrifugal blower with coaxial impellers is considered. Experimental dependences on the establishment of pressure flow and power characteristics are presented. Based on the accounting of hydraulic losses, the energy efficiency of the design of the pumping unit with the coaxial arrangement of the impellers was assessed. Practical value. The new design of a centrifugal pump with coaxial impellers reduces hydraulic losses by more than 23% compared to traditional designs of centrifugal pumps. The results of the work can be used by design, research, and industrial organizations engaged in the design and operation of pumping equipment.

Effects of Innovative Suction Slots on the Performance of a Radial Bladed Impeller of a Centrifugal Blower - A Numerical Transient Analysis

Effects of Innovative Suction Slots on the Performance of a Radial Bladed Impeller of a Centrifugal Blower - A Numerical Transient Analysis

Use of the Principal Component Analysis for Classification of Aircraft Components Failure Conditions Using Vibrodiagnostics

Safety and trouble-free operation are important factors that places aviation among the safest forms of transport. These parameters are achieved mainly by state-of-the-art diagnostic and maintenance programs and methods, which are constantly evolving and increasing their efficiency. The manuscript is focused on the use of a centrifugal blower, on which fault states were artificially simulated and subsequently analyzed by statistical methods not normally used in the field of vibrodiagnostics. The use of principal component analysis (PCA) method played a key role in evaluating the vibrodiagnostic signal of the measured device. The PCA method enabled the categorization of fault conditions and provided a unique view of diagnostic methods with reference to specific signals. The results of the presented research indicate the potential of the PCA method in practice and in the need to carry out further research for other fault conditions. The implementation of such a tool is a prerequisite for more effective determination of specific fault conditions and the use of the PCA method in vibrodiagnostics not only in aviation but also in general industry.

ВЫБОР И ОПТИМИЗАЦИЯ ОСНОВНЫХ ПАРАМЕТРОВ ТУРБОКОМПРЕССОРОВ ПРИ ПРОЕКТИРОВАНИИ И ДОВОДКЕ ГТД

The choice and optimization of the rotational speed, the number of stages, the axial velocities distribution, reactivity, diametric dimensions and flow path shape, the blade rows width, changes in the height of the flow path in the compressors and turbines of the gas turbine engine are considered. The method for determining the total pressure recovery ratio and its relationship with the efficiency of blade rows, stages, compressors and turbines is proposed. It is shown that with the same value of this indicator in these elements, the maximum efficiency of compressors and turbines in the composition of turbocompressors is achieved. It is proposed to use this indicator at an early design stage to determine the optimal stages number and the work distribution between them, the change in work along the flow path height. It is shown how the position of the points for the stages and the optimal flow path shape are determined on the Smith diagrams. Various methods are proposed for parameters choosing of the blade profiles for the first, last and for intermediate steps. It is shown how these methods are used when fine-tuning compressors and turbines based on the results of GTE tests. The results of approbation of the developed design and refinement methods are given on examples of changing the geometry of the blade rows and the flow path in the replaceable flow path of the centrifugal blower for the R-16 "Ufa" gas compressor unit, the refinement of the 3-stage LPC for perspective two spool turbofan engine, comparison with the results of simulation in the DVIGw system , 2D and 3D CAD / CAE-modeling.

Determination of Fuel Gas Flow Rate in Gas Pumping Unit and Compressor Station

Formulas for drive power of centrifugal supercharger of natural gas are obtained, where efficiency factor (EF) of centrifugal supercharger is equal to product of three EF of centrifugal supercharger: mechanical, polytropic, gas-dynamic. The gas dynamic EF of the centrifugal supercharger is usually not taken into account and is taken equal to one. Gas dynamic EF takes into account the pressure loss of the centrifugal supercharger pumped in the stages and the energy loss due to friction of the centrifugal supercharger impellers in the gas medium. Also in the formula of calculation of drive power of the operated centrifugal supercharger the presence of condensate and water vapors in the natural gas is taken into account, which affects the accuracy of measuring the flow rate of pumped gas in the diaphragm flowmeter. Pumping of pure natural gas is impossible in reality and there are always impurities in natural gas, which must be taken into account to estimate the mass flow rate of gas. For formulas of practical (operated) and theoretical calculations of the drive power of the centrifugal natural gas blower received constant (equal to 0.004) for daily standard gas flow, which simplifies the calculation. The paper presents both precise and simplified formulas for the drive power of a centrifugal natural gas blower.

Numerical Model of a Deep Surge Cycle in Low-Speed Centrifugal Compressor

Abstract In this article, a numerical model of the full surge cycle is presented for the low-speed centrifugal blower and compared with the experiment. Surge phenomenon is very dangerous for the compressor operation. Therefore, the possibility of studying its physics experimentally is strongly limited. The application of numerical methods allows one to safely analyze surge physics without causing risks to the operating crew. This article presents a description of the applied numerical method and exhaustive analysis of the flow structures observed at consecutive stages of the surge cycle. The surge is known to be very difficult to be simulated due to large timescale and region of influence. This study also shows the importance of an appropriate choice of the simulation definition and the boundary conditions. The presented method allows gathering information about features such as the regions of flow reversal, pressure distributions, pressure rise, cycle frequency, and others. All the aforementioned information provides important input to the efficient antisurge system design. The model has been validated by a comparison with the experimental data. Thanks to simulation, standardized antisurge solutions could be possibly replaced with more efficient protection schemes tailored to a given machine.

Inspection of Centrifugal Blower by Varying Different Blade Configuration using CFD

This examination points towards the advancement of an enhanced plan of a radiating blower comprising of different fan ribs, in light of execution appraisals looking like its inside parts. Different segments, for example, the outside cases and the turning fan ribs set in an assortment of working conditions, for example, fluctuating impeller speed and number of edges, are assessed mathematically and tentatively. Assessment depends on execution boundaries, including the delta and outlet pressures, stream rate, force, and intensity of the radial fan. The mathematical examination recommends that the blend of the different pivoting outline strategy and the standard k-ε disturbance model was suitable for recreation of the inside stream qualities and for power forecast. The mathematical outcomes were contrasted and tests under deliberately planned trial conditions. Plan and displaying of Impeller and packaging has been completed in CATIA V5R21 and then the Calculation was imported to Ansys 16.0. By differing the quantity of fan ribs, the exhibition fluctuates practically nothing. Nonetheless, the FC fan ribs display the best exhibition in regards to their stream rate reaction and are related with most reduced force. The weight at the exit is diminished as the stream rate is expanded. Among all the fans, the FC fan would yield the most noteworthy stream rate.

Numerical Modeling and Simulation of a Volumetric Resistance Blower Using Porous Rotor

Abstract This paper presents an experimentally validated modeling methodology for a new type of blower design known as volumetric resistance blower (VRB). It replaces the traditional centrifugal blower fan blades with a continuous porous medium disk and has been reported to be capable of providing a lower acoustic noise for the same output flow compared to a traditional blower. A three-dimensional transient numerical model of VRB is developed which incorporates the movement of a porous rotor using experimentally determined foam parameters to characterize the porous drag effect and a sliding mesh to simulate the rotation effect. The numerical results are validated with experimentally determined fan curve over broad range of operating conditions. The effect of the foam resistance parameters on the flow characteristics is investigated which serves the rationale for the optimization of these parameters. The model is used to study the sensitivity of the VRB performance to foam parameters using different types of commercially available open-cell reticulated foam.

Thermal Analysis on Pin-Fins With Hexagonal & Threaded Geometry In Natural and Forced Convection

In the present work of heat transfer for hexagonal fins (1mm & 2mm) grooves on surface and threaded fin is addressed. The test has been performed on three different fin geometries having hexagonal (1mm)groove, hexagonal(2mm)groove, threaded fin(0.5mm)pitch and test performed by using a centrifugal blower, test section, heater and test panel and Results are obtained for temperature distribution, effectiveness, efficiencies at a same flow rate of air as it was conducted in forced convection and the same parameters considered for different values are obtained for natural convection with different fins as well. In this experiment for forced convection, the airflow rate is constant i.e, 2.3371 m/sec throughout the experiment. In natural convection, efficiency for the threaded fin is high with 93.89% and effectiveness of hexagonal(2mm)depth fin is 28.11. In forced convection, the efficiency of the threaded fin is high with 81.83% and effectiveness of hexagonal(1mm)depth fin is high with 23.51 was recorded. The heat transfer rate is higher in natural convection is hexagonal(2mm)depth fin with 11.41 watts and 21.75 watts in forced convection with hexagonal(1mm)depth fin

К вопросу об оценке пожарной безопасности рабочих мест персонала компрессорных цехов газотранспортных предприятий

The method is considered related to fire safety evaluation of the workplaces located in the engine room of the compressor shop. The method is based on the methodology for evaluating safety of the systems at various levels (workplace, shop, enterprise). The method of constructing a scenario for the occurrence and development of a fire using cause and effect diagram (Ishikawa Diagram) based on the principle of «action — reaction» is shown. The mathematical model for assessment of the probability of implementing a fire scenario at a production facility, and the model for assessment of the probability of personnel evacuation in case of fire are considered. When developing a model for assessing the likelihood of personnel evacuation, the results of studies were used related to the time of the beginning of people evacuation conducted by the State Fire Service Academy of EMERCOM of Russia. The results of experiments on the evacuation of personnel from the technological structure of gas processing plant and from the compartments of gas-pumping unit are also shown.  The results of the practical implementation of the proposed approach on the examples of constructing fire scenario and assessment of the possibility of fire occurrence due to surge of the operating point of a centrifugal blower are presented.  The likelihood of the specified fire scenario occurrence is estimated. The estimation of the likelihood of personnel evacuation in case of fire in the engine room of the compressor shop is presented. The options for calculating the time of evacuation of the employees based on the specific conditions, parameters that characterize the specifics of people behavior in case of fire, as well as the reliability of the notification and evacuation management system are proposed. Comparison is made between the suggested models and the models used in the normative documents in the field of fire safety on the example of the evacuation of the compressor shop personnel located at the time of fire in the compartments of gas pumping unit. It is shown that the developed models allow for a more complete assessment of all the factors that affect the probability of employee evacuation. The option of using the proposed models for calculating an individual risk value, which is proposed to be considered as a criterion for the assessment of the workplaces fire safety, is discussed in the article.

Effect of nano cupric oxide coating on the forced convection performance of a mixed-mode flat plate solar dryer

In this study, mixed mode solar dryer of forced convection type, integrated with a CuO nanoparticle coated flat plate solar collector was developed and its effectiveness of drying maize under the meteorological conditions of Coimbatore, India was evaluated. The aforementioned setup entails a solar collector (flat plate type) with 3 drying trays and a centrifugal blower. The conventional solar absorber plate was made up of aluminium, which was coated with black paint. Another modified solar absorber plate was made up of aluminium with a coating of black paint with two different vol% of CuO nanoparticles (0.02% and 0.04%), for improving the heat transfer rate. Performance tests on the modified dryer were carried out at constant air flow rate (1.5 m3/min) and the results were compared with the conventional type. The efficiency of the collector got improved by 4% while using black paint with 0.04 vol% of CuO nanoparticle coated absorber. Also the drying time got reduced by 6%, when compared to conventional type dryer. Also the collector temperature recorded in the black paint with 0.04 vol% CuO nano-particle coated collector was higher compared to black paint coated and black paint with 0.02 vol% CuO nanoparticle coated collector.