Fan Performance Research Articles

G100S axial flow fan simulation comparison analysis

This paper conducts a comparative simulation for different structural layout schemes of the new G100S axial flow fan, with the motor layout position and its supporting guide vane as the main modification direction, while the fan length and guide tongue angle are appropriately adjusted according to the motor position. CFD analysis and calculation are used to compare and study the performance of the axial-flow fan. The results show that the axial flow fan with rear motor, air outlet cone integration, and large angle guide tongue layout has greater wind speed, longer injection distance, more uniform distribution of outlet flow field traces, greater wind pressure at the air outlet, and faster flow stability convergence. This work will provide technical support for designing orthogonal experiments in the direction of fan miniaturization and lightweight.

Volute Optimization Based on Self-Adaption Kriging Surrogate Model

Optimizing the volute performance can effectively improve the efficiency of a centrifugal fan by changing the volute geometric parameter, so the self-adaption Kriging surrogate model is used to optimize the volute geometric parameter. Firstly, volute radius Rd, the radius of tongue r, and outlet angle of the volute θ are selected as the optimization parameters of the volute, and latin hypercube sampling is used to configure the initial sample points, the corresponding three-dimensional aerodynamic model under each sample point configuration is constructed. CFD software is used to simulate the aerodynamic efficiency and total pressure of the centrifugal fan under each initial sample point configuration. Secondly, the Kriging surrogate model of initial sample point configuration parameters, aerodynamic efficiency, and total pressure of volute is constructed, and sample points are added by expectation improvement (EI) method to improve the fitting accuracy of Kriging surrogate model. Finally, the high-precision Kriging surrogate model is used as the fitness function of NSGA-II algorithm to find the Pareto optimal solution under multiobjective optimization, and the optimization target are aero dynamical efficiency and total pressure. The rationality of the above method is verified by optimizing the 9–19.4A type centrifugal fan volute. The efficiency of the optimized fan under working conditions is increased by 1%, and the total pressure under working conditions is not reduced. The optimized volute can effectively improve the overall performance of the centrifugal fan. This study is helpful to promote the application of numerical optimization design method in the volute of centrifugal fan. It provides reference for the optimization design of high-performance centrifugal fan.

Uniformity Index as a Universal Air-Cooled Condenser Fan Performance Metric

Ambient wind has a negative effect on mechanical forced-draft direct air-cooled steam condenser (ACC) fan volumetric performance, and increases dynamic fan blade loading. Investigating these effects directly using on-site measurement or numerical analysis is complicated, and most previous work has focused on only one effect at the expense of the other. In this study, fan axial velocity inflow uniformity is identified as a single metric offering the potential to holistically qualify ACC fan operation under windy conditions. A 3 × 6 fan cell ACC was modelled with CFD using a blade element theory-based fan model, and clear relationships between the fan inflow uniformity index and both fan volumetric performance and dynamic blade loading were observed in the results. The same relationships were observed in on-site test data collected at a single ACC fan, thus validating the numerical results. The uniformity index can be used in both numerical and experimental work as a means of investigating both fan volumetric performance and dynamic blade loading with less computational and measurement complexity; it also offers a potentially useful means of quantifying the severity of fan operating conditions, to assist with more reliable case-specific fan design and selection.

Application of Digital Twins and Metaverse in the Field of Fluid Machinery Pumps and Fans: A Review

Digital twins technology (DTT) is an application framework with breakthrough rules. With the deep integration of the virtual information world and physical space, it becomes the basis for realizing intelligent machining production lines, which is of great significance to intelligent processing in industrial manufacturing. This review aims to study the application of DTT and the Metaverse in fluid machinery in the past 5 years by summarizing the application status of pumps and fans in fluid machinery from the perspective of DTT and the Metaverse through the collection, classification, and summary of relevant literature in the past 5 years. The research found that in addition to relatively mature applications in intelligent manufacturing, DTT and Metaverse technologies play a critical role in the development of new pump products and technologies and are widely used in numerical simulation and fault detection in fluid machinery for various pumps and other fields. Among fan-type fluid machinery, twin fans can comprehensively use technologies, such as perception, calculation, modeling, and deep learning, to provide efficient smart solutions for fan operation detection, power generation visualization, production monitoring, and operation monitoring. Still, there are some limitations. For example, real-time and accuracy cannot fully meet the requirements in the mechanical environment with high-precision requirements. However, there are also some solutions that have achieved good results. For instance, it is possible to achieve significant noise reduction and better aerodynamic performance of the axial fan by improving the sawtooth parameters of the fan and rearranging the sawtooth area. However, there are few application cases of the Metaverse in fluid machinery. The cases are limited to operating real equipment from a virtual environment and require the combination of virtual reality and DTT. The application effect still needs further verification.

Aerodynamic performance improvement and noise control for the multi-blade centrifugal fan by using bio-inspired blades

Inspired by the swimming characteristics of carps in the C-shaped starting posture, the bionic design of the blade is developed to improve the aerodynamic performance, reduce noise and conserve energy of multi-blade centrifugal fans. By adopting the reverse engineering method, the bionic equal-thickness blades (BETBs) inspired by the C-shaped starting mid-arc of carp are designed and optimized. Based on the comparison between numerical and experimental results of the aerodynamic performance of fan, the optimal bionic equal-thickness blade (O-BETB) is obtained. When the O-BETEs are applied to the original fan, the flow rate is increased by 6.8% and the noise is reduced by 0.5 dB(A). Further, the reconstructed geometric profile of fish body is coupled into the O-BETB to improve the aerodynamic performance of the fan. The results show that the flow rate with the coupled bionic blades (CBB) is increased by 8.3%, while the noise is reduced by 1.1 dB(A), and the power and efficiency are also optimized. The internal flow field, sound field and acoustic characteristics are analyzed to reveal the generation mechanism of aerodynamic noise. The aerodynamic noise of the fan is mainly concentrated in the low and middle frequency range, and its propagation process has obvious dipole characteristics. Meanwhile, because the profile of CBB is more in line with the flow characteristics in the fan, the separation vortex and secondary-flow vortex in the impeller channel and the unsteady interaction between the blade wake-flow and the volute are significantly suppressed, which is also the main reason for the CBB to reduce the noise.

Improving the performance of ducted fans for VTOL applications: A review

Improving the performance of ducted fans for VTOL applications: A review

A Data-Driven Tip Flow Loss Prediction Method for a Transonic Fan Under Boundary Layer Ingesting Inflow Distortion

Abstract In a boundary layer ingesting (BLI) propulsion system, the fan blades need to operate continuously under large-scale inflow distortion. The distortion will lead to serious aerodynamic losses in the fan, degrading the fan performance and the overall aerodynamic benefits of the aircraft. Therefore, in the preliminary design of a BLI propulsion system, it is necessary to evaluate the influence of the fuselage boundary layer under different flight conditions on the fan aerodynamic performance. However, a gap exists in the current computational methods for BLI fan performance evaluations. The full-annulus unsteady Reynolds-averaged Navier–Stokes (URANS) simulations can provide reliable predictions but are computationally expensive for design iterations. The low-order computational methods are cost-efficient but rely on the loss models for accurate prediction. The conventional empirical or physics-based loss models show notable limitations under complex distortion-induced off-design working conditions in a BLI fan, especially in the rotor tip region, compromising the reliability of the low-order computational methods. To balance the accuracy and cost of loss prediction, the paper proposes a data-driven tip flow loss prediction framework for a BLI fan. It employs a neural network to build a surrogate model to predict the tip flow loss at complex non-uniform aerodynamic conditions. Physical understandings of the flow features in the BLI fan are integrated into the data-driven modeling process, to further reduce the computational cost and improve the method’s applicability. The data-driven prediction method shows good accuracy in predicting the overall values and radial distributions of fan rotor tip flow loss under various BLI inflow distortion conditions. Not only does it have higher accuracy than the conventional physics-based loss models but also needs much less computational time than the full-annulus time-accurate simulations. The present work has demonstrated a significant potential of data-driven approaches in complex aerodynamic loss modeling and will contribute to future BLI fan design.

Experimental and numerical investigation on conjugate performance of fan and heat exchanger of helicopter oil cooling system

• The overall performance of axial fan was studied with two flowrate adjusting modes. • HEs with different fin structures and flow lengths were designed and fabricated. • Coupling performances of fan and different HEs were studied experimentally. • The flow field of oil cooling system at different air flow rate was simulated. • The performance curves obtained by two modes form a hysteresis region. In this article, a combined experimental and numerical study has been performed to investigate the operating performance of axial fan and oil cooling system. A test rig was established, and six types of plate-fin heat exchangers (HEs) with offset strip and rectangular fins and three different flow lengths of 30 mm, 60 mm and 90 mm at side were designed and manufactured. The performance of an axial fan with front guide vane was experimentally studied by two different adjusting modes: gradually increasing and decreasing air flow rate. The conjugate performances of the axial fan and different HEs were discussed in detail. Moreover, a three-dimensional (3D) model was developed to investigate the flow distribution of the system including fan and 30 mm offset strip fins HE at different flow rates. The results show that: (1) the total pressure performance curve of the axial fan under two adjusting modes could form a hysteresis region near the stall boundary. In the hysteresis region, the fan performance curves showed significant difference under both adjusting modes; (2) when the offset strip fins HE with large flow resistance is considered, the system could have two theoretical working points in the hysteresis region. For the case of HE with 90 mm offset strip fins, the flow rates of the system at two theoretical working points were 25.1 m 3 /min and 34.2 m 3 /min, and the heat transfer capacity of the HE were 23.1 kW and 27.5 kW, respectively. In the current experiment, it was found that the system operated at the point with smaller flow rate; (3) when the HE flow resistance exceeded a certain value, the boundary layer separation of the airflow could occur at the rotor blade. The separation had a small effect on the inlet airflow due to its turbulence kinetic energy was low and basically the same at each blade passage. Therefore, the system did not surge or stall at small flow rate.

Desain Prototype Alat Kontrol Serta Deteksi Suhu dan Kelembaban Kandang Ayam Broiler Dengan Metode Fuzzy Berbasis IoT

<p><em>In this study, the authors designed the control of temperature and humidity detection in chicken coops using the IoT-based Fuzzy method. Control prototype design and detection of temperature and humidity of broiler cages using IoT-based fuzzy methods, and can be monitored remotely with a smartphone using several components, namely NodeMCU ESP32 as a data processor and controller between the Dht-11 temperature sensor and the output in the form of an LCD to determine the temperature of the cage. directly and also in the form of Smartphone communication data via the internet network with Blynk software. the DHT-11 sensor is in charge of reading the temperature and humidity of the chicken coop, the LCD serves to provide a direct display of the results of the temperature and humidity monitoring data parameters, the blynk application itself is tasked with displaying sensor parameters remotely on a smartphone which in the blynk software can monitor or get notification if the temperature state is crossing a predefined threshold. All components require 24V voltage generated by the 220V SMPS power supply to 24V DC. </em><em>The use of fuzzy rules in temperature and humidity control can regulate the output performance of lights and fans that work according to the specified rules.</em></p>

Multi-Objective Optimization of Rear Guide Vane of Diagonal Flow Fan Based on Robustness Design Theory

As an essential fluid machine in national production, the optimal design of the performance of fans has long been a focus of research. In the format of small diagonal flow fans with rear guide vanes, there are too many design variables, and the design parameters interact with each other, resulting in a degradation of the fan’s performance under actual operating conditions. Under realistic conditions, many uncertainties exist in the object of study and fluctuations in variables and parameters lead to a specific deviation of the optimization target from the design target. A method is needed for the robust and optimal design of angular flow fans under stochastic operating conditions of the design variables. In this paper, a multi-objective aerodynamic performance powerful design method is proposed using Pearson correlation analysis, combined with CFD calculation method, Latin hypercube experimental design and the Kriging agent model, to optimize the rear guide vane structural parameters of the diagonal flow fan under uncertain aerodynamic performance conditions, analyze the flow field characteristics before and after the modification, and select the optimal design model for the release. The test results show that the total pressure of the optimized fan is increased by 86 Pa, and the noise is reduced by 2.4 dB. The proposed optimization method is effective and can also be used to optimize the performance of other types of fans.

Aerodynamic Characteristics of a Ducted Fan Hovering and Transition in Ground Effect

Ducted fans installed on vertical takeoff and landing vehicles experience significant ground effect during takeoff and landing. The aerodynamic characteristics of a ducted fan hovering and transitioning in the ground effect are studied using numerical simulations in this paper. The flowfields are obtained by solving Reynolds Averaged Navier–Stokes equations with the Multiple Reference Frame approach. When a ducted fan hovers in the ground effect, the blade thrust increases due to the combined effect of the increase in the effective angle of attack of the blade and the increase in ambient pressure; the duct thrust decreases due to the combined effect of the decrease in the effective angle of attack of the duct and the increase in ambient pressure. Stall occurs at a certain advance ratio and angle of attack when transitioning in the ground effect. The ground effect delays the occurrence of stall at some advance ratios. The ground effect is hardly detectable at angles of attack less than 30° even if the height drops to 0.5 times the duct exit diameter. At this height and high angles of attack, the different positions and influence regions of the ground vortex at different advance ratios contribute to the different variation trends in the ducted fan performance.

Enhancement of piezoelectric fan cooling by geometrical arrangements

Piezoelectric fan cooling is drawing growing attention for its compact size and high energy efficiency. However, its cooling capacity is not good enough and needs to be maximized to catch up with the industry demand. In this work, we aim to increase heat transfer performance by varying piezoelectric fan locations and channel configurations. The effect of fan location is firstly studied. By tuning the fan position, a higher streamwise velocity is achieved, thus increasing the heat transfer. A fan inserted into the channel achieves a 55% enhancement on the Nusselt number compared with natural convection. On top of this, the effect of the channel configuration is explored. Both expansion and contraction configurations benefit heat transfer, and the optimal one adds a further 10% enhancement on top of the parallel configuration case. That is, the maximum cooling enhancement is 70% compared with natural convection. The fan motion is captured by a high-speed camera. Flow visualization is used to investigate the flow pattern. The channel streamwise fluid velocity is examined. It is found that the contraction configuration boosts the streamwise velocity and generates a jet flow pattern at the channel outlet. The expansion configuration significantly alters the flow motion with more vortices in a longer transmission distance, yielding a stronger spanwise mixing. The findings demonstrate that geometrical arrangements can substantially enhance the heat transfer performance of the piezoelectric fan, thus paving the way for tackling the urgent cooling requirement.

Mathematical Model of Air Dryer Heat Pump Exchangers

This paper presents a mathematical model of heat pump exchangers and their thermal interaction with a fan for an air dryer. The calculation algorithm developed for the finned heat exchangers is based on the ε-NTU method, allowing the determination of air side and refrigerant side heat transfer coefficients, evaporator and condenser heat capacity and air parameters at the dehumidifier outlet with known exchanger geometries, initial air parameters and mass flow rate. The model was verified on an industrial dehumidifier test bench. This enabled the heat transfer coefficients for the exchanger to be calculated as a function of the speed and, therefore, the power of the fan’s drive motor. An increase in fan performance on the one hand results in an increase in the heat transfer rate, but, on the other hand, it causes an increase in the total energy consumption of the motor. Thus, while it causes an increase in drying capacity, it also causes an increase in the energy consumption of the dehumidifier. In order to optimise the unit in terms of energy consumption, it is therefore necessary to determine a function that relates the amount of heat exchanged to the efficiency of the fan.

Effect of blade number on the performance of centrifugal fan

The present-day energy crisis challenges the engineers to take careful steps in design of fans. Enhancing the performance of centrifugal fan through parametric analysis is one of the ways. Simulation of centrifugal fan is demonstrated by considering a preliminary design model of backward curved bladed impeller centrifugal having 11 blades (MD1) which is designed using theoretical concepts from fan handbooks to achieve an air capacity of 7 m3/s producing a total pressure at outlet of fan to be 2000 Pa while impeller running at 1500 RPM which is the industrial requirement. Solid model is created and simulation is performed to analyze the fluid flow using Computational Fluid Dynamics (CFD). Results of this preliminary model show that a total pressure of 1323.07 Pa at the outlet of fan is achieved with an efficiency of 50.82%. Need for improvement in performance and to the study of effect of blade number on the model has led to perform simulations by varying the number of blades of impeller to Z = 8, 10, 12, 14 while keeping all the parameters identical to the design point condition. Contour plots of flow and velocity vectors in the blade passages areas for different cases along with the total pressure and efficiency are compared. Assessment of these results shows that when blade number Z = 14, there is an increase in total pressure by 21.77% and efficiency by 5.74% in comparison with design point condition. The centrifugal fan is simulated successfully as the residuals shows good convergence of <10−5.

Performance and exergy analysis of solar-operated vacuum fan and external condenser integrated double-slope solar still using various nanofluids.

Productivity, distillate exergy, and energy efficiency of the conventional passive single-basin double-slope solar still is minimum, due to low evaporation and condensation rate. This research article attempts to increase the production rate, distillate exergy, and energy efficiency of the single-basin glasswool-insulated double-slope solar still by attaching novel solar-operated vacuum fan, external condenser and adding 0.1% volume concentration of copper oxide, aluminium oxide, and zinc oxide nanofluid. Inclusion of vacuum fan and external condenser enhances the production rate in the modified solar still. It is evident that as the vacuum fan exhales the vapour in the basin, the temperature of water in the basin and transparent glass are reduced significantly and so the vaporization amount increases considerably. It makes that a large amount of vapour is extracted by the vacuum fan and allowed to pass though the condenser, and therefore, the entire condensate of the solar still is increased significantly. To attain a comparative study, conventional and modified double-slope solar still of identical dimensions were developed utilizing aluminium and an experimental investigation carried out during the peak of summer. The inclusion of solar-operated vacuum fan and external condenser in the modified glasswool insulated double-slope solar still enhances the maximum energy efficiency, exergy efficiency, and cumulative production by 28.37%, 78.60%, and 64.29% due to enhancement in the evaporation rate of liquid in the solar still basin. Also, the addition of 0.1% volume concentration of copper oxide, aluminium oxide, and zinc oxide nanofluid in the conventional double-slope solar still possess the maximum increase in the energy efficiency and exergy efficiency by 20.96%, 18.01%, 10.76% and 52.53%, 38.52%, 30.35% as compared to conventional solar still without nanofluid. It is primarily due to increase in the thermal conductivity and radiative property of nanofluid. The result also signifies that the addition of 0.1% volume concentration of copper oxide, aluminium oxide, and zinc oxide nanofluid in the modified double-slope solar still possess the maximum enhancement in the energy efficiency and exergy efficiency by 21.33%, 19.36%, 17.03% and 50.11%, 36.82%, 23.75% as compared to modified solar still without nanofluid. Combined effect of using solar-operated vacuum fan, water cooled condenser, and 0.1% volume concentration of copper oxide, aluminium oxide, and zinc oxide nanofluid in the double-slope solar still enhances the maximum production rate and cumulative production by 59.26%, 55.56%, 51.85% and 96.43%, 82.14%, 75% as compared to conventional double-slope solar still. Among the three different nanofluids, the copper oxide nanofluid produced the highest cumulative production, energy efficiency, and exergy efficiency.

DESIGN FEATURES OF THE HEATING CHAMBER OF THE MILL BALL TEMPERING FURNACE AND CALCULATED THERMAL MODES OF ITS OPERATION

The article considers the design of the heating chamber consisting of single sections equipped with the same type of block-type devices. Heating of the metal in the block is carried out by the jet blowing the surface of the balls with a heated gas flow circulating inside its body using a high-temperature fan. On the basis of the proposed method, a computational analysis of several thermal modes of operation of the heating chamber, consisting of five sequentially installed single sections, was carried out. The section consists of housing and a jet heating unit placed inside. The unit is a sheet steel structure, inside which, by means of a nozzle system and a high-temperature fan, a circulation circuit is organized, which is necessary for the movement of the heat carrier. The heat carrier is heated by a burner. The balls are stacked in one row and move inside the furnace body by means of a conveyor. The effect of changing the performance of the circulation fan on the parameters of the furnace has been studied. An analysis of the obtained calculated data showed that with a constant furnace performance, the heating mode of the balls is determined by the ratio of the coolant temperatures and the fan performance. Doubling the performance of a fan of a single section from 14,000 m3/h to 28,000 m3/h leads to a decrease in the required coolant temperature by 30% from 572 °C to 434 °C, while the efficiency of the heating chamber remains unchanged equal to 0.71. An increase in performance of a fan leads to a decrease in the temperature of the pumped gas, which contributes to an increase in the reliability of its operation by maintaining the normal thermal regime of the running gear. The materials presented in the article can be useful in the development and design of convective furnaces.

A fast computational method of the aerodynamic performance of fan and booster with inlet distortion

A fast computational method of the aerodynamic characteristics of fan and booster with inlet distortion is developed in this paper. This method is based on a time-marching throughflow model, and the governing equations are circumferentially averaged Navier-Stokes equations. A model of distributed inviscid blade force and viscid blade force is adopted to reproduce the flow deflection and loss. The deviation angle and loss parameters are interpolated from a database which is extracted from 3-D simulation results of compressor with uniform inlet. After a validation case is performed, the aerodynamical performances of a multistage fan and booster with inlet radial and circumferential distortion are computed. The results show the predictive ability of this method, and the acceptable computational time cost indicates the future application potential of this method during the design stage of a new turbomachinery.

Numerical Investigations of a Non-Uniform Stator Dihedral Design Strategy for a Boundary Layer Ingestion (BLI) Fan

A distributed propulsion system has the advantage of saving 5–15% fuel burn through ingesting the fuselage boundary layer of an aircraft by fan or compressor. However, due to boundary layer ingestion (BLI), the fan stage will continuously operate under serious inlet distortion. This will lead to a circumferentially non-uniform flow separation distribution on the stator blade suction surface along the annulus, which significantly decreases the fan’s adiabatic efficiency. To solve this problem, a non-uniform stator dihedral design strategy has been developed to explore its potential of improving BLI fan performance. First, the stator full-annulus blade passages were divided into blade dihedral design regions and baseline design regions on the basis of the additional aerodynamic loss distributions caused by BLI inlet distortion. Then, to find the appropriate dihedral design parameters, the full-annulus BLI fan was discretized into several portions according to the rotor blade number and the dihedral design parameter investigations for dihedral depth and dihedral angle were conducted at the portion with the largest inflow distortion through a single-blade-passage computational model. The optimal combinational dihedral design parameter (dihedral depth 0.3, dihedral angle 6 deg) was applied to the blade passages with notable flow loss which were mainly located in the annulus positions from −120 to 60 degrees suffering from inlet distortion, while the blades in the low-loss annulus locations were unchanged. In this way, a non-uniform stator dihedral design scheme was achieved. In the end, the effectiveness of the non-uniform stator dihedral design was validated by analyzing the internal flow fields of the BLI fan. The results show that the stator dihedral design in distorted regions can increase the inlet axial velocity and reduce the aerodynamic load near the blade trailing edge, which are beneficial for suppressing the flow separations and reducing aerodynamic loss. Specifically, compared with the baseline design, the non-uniform stator dihedral design has achieved a reduction of aerodynamic loss of about 7.7%. The fan stage has presented an improvement of adiabatic efficiency of about 0.48% at the redesigned point without sacrificing the total pressure ratio. In the entire operating range, the redesigned fan has also shown a higher adiabatic efficiency than the baseline design with no reduction of the total pressure ratio, which provides a probable guideline for future BLI distortion-tolerant fan design.

The matching characteristics and flow mechanisms of partial-height booster rotor and fan rotor for a high-throughflow fan

Further enhancements in the throughflow capacity of the conventional fan in the turbofan engine are limited by its aerodynamic and geometric parameters, but the concept of a high-throughflow fan is expected to overcome this limitation. This study explored the effects of the parameters of axial overlap ( AO) and percent pitch ( PP) on the aerodynamic performance of a high-throughflow fan by using validated numerical simulations to clarify the complicated mechanisms of the tandem rotor. The results showed that the tandem rotor determined the overall stage performance. The isentropic efficiency and total pressure ratio of the tandem rotor reached the best as AO = +10%, and PP = 20%. When PP was small and AO changed, the stronger passage shock wave in the fan rotor ( FR) was the main factor influencing the aerodynamic performance of the tandem rotor. While PP enlarged to a high level and AO changed, interactions between the tip vortex or wake and the low-energy fluids of the FR pressure surface ( PS), and the strength of the passage shock wave in the FR determined the isentropic efficiency, which was slightly different from the lower PP.

Designing the right impellers for your fan applications

Impeller design and specification is critical to fan performance in all applications, and especially when operating in harsh operating environments.