Static Pressure Differences Research Articles

Modeling of erosion wear in labyrinths seals using CFD approach

This study addresses erosion rates in labyrinth seals (LS) using Finnie’s model to assess the effect of particle impact on Ti-6Al-4V alloy. Erosion wear was investigated based on Ti alloy’s density and surface hardness and modeled using COMSOL with incompressible Navier-Stokes equations for turbulent [Formula: see text] flow. SiC spherical particles of 100[Formula: see text]m, 150[Formula: see text]m, and 200[Formula: see text]m were added to the model, with inlet velocities corresponding to Reynolds numbers 200 and 2000. Results demonstrated that for Re = 200, the erosion rate reached a maximum of [Formula: see text] mg/m2s on the initial labyrinth teeth, while at Re = 2000, erosion decreased to 0.15 mg/m2s. The rotation of the rotor reduced leakage by 0.64% under static conditions and pressure differences were reduced by up to 22.56% for low inlet velocities. The hardness and density of the Ti alloy have negligible impact on erosion. The study highlights Finnie’s model feasibility for predicting erosion, providing the fundamentals for optimizing LS designs in turbomachinery.

The Energy Consumption Comparison of Temperature Difference-based Defrosting Exit Method and Time-based Defrosting Exit Method with Various Static Pressure Differences

The time-based defrosting exit method(TDEM) has been widely used in cold storage, but the issue of energy consumption has been heavily criticized. In this paper, a temperature difference-based defrosting exit method(TDDEM) is proposed to compare with TDEM. Firstly, a parameter acquisition system of cold storage is constructed, and the experimental setup is conducted to determine the experimental parameters. Subsequentially, the range of defrosting static pressure difference is determined based on pre-frosting experiment, and the defrosting experiment of TDEM and TDDEM are carried out at five various static pressure difference conditions, 16Pa, 14Pa, 12Pa, 10Pa and 8Pa, respectively. The results show that the temperature fluctuations per defrosting events of TDEM are more severe compared to TDDEM, with with average increases of 102.2%, 91.6%, 59.3%, and 46.5%, respectively. Energy consumptions of TDDEM are markedly lower than TDEM, with reductions of 21.4%, 15.7%, 14.09% and 14.59%, respectively. Whether TDEM or TDDEM, the lowest energy consumption is occurred at 10Pa, and highest is 8Pa.

Numerical Simulation and Analysis of the Airflow Field in the Crushing Chamber of the Hammer Mill.

The airflow dynamics within hammer mills' crushing chambers significantly affect material crushing and screening. Understanding the crushing mechanism necessitates studying the airflow distribution. Using a self-built crushing test platform and computational fluid dynamics (CFD) simulations, we investigated the impact of screen aperture size, rotor speed, hammer-screen clearance, hammer quantity, and mass flow rate on airflow distribution within the rotor region, circulation layer, and screen apertures. Results indicated generally uniform axial static pressure distribution within the rotor region, with radial gradients. Increased rotor speed improved radial static pressure gradients, while higher mass flow rates reduced them. The highest airflow velocity within the circulation layer reached approximately 83.46% of the hammer tip's tangential velocity. Greater rotor speed and hammer quantity intensified circulation airflow, whereas increased mass flow rate decreased it. Eddies formed within screen apertures with higher rotor speeds and hammer quantities but diminished with larger apertures and higher mass flow rates. Static pressure differences across screen apertures increased with mass flow rate and rotor speed but decreased significantly with larger apertures. This systematic examination provides insights into airflow distribution within hammer mill crushing chambers, offering a theoretical foundation for improving and designing hammer mills.

Numerical Simulation of the Dovetail Tee and Hydraulic Optimization of the Height Difference for Pipeline in a Liquefied Natural Gas Filling Station

Certain configurations of liquefied natural gas refueling stations exhibit a deficiency in managing boil-off gas. Furthermore, the ill-conceived linkage between the submersible pump and the gas storage tank pipeline leads to impeded natural gas transmission. This study employed the computational fluid dynamics (CFD) methodology to scrutinize the hydrodynamic attributes of the T-type tee and dovetail tee configurations implemented in the pipeline design connecting the submersible pump and storage tank in a liquefied natural gas (LNG) filling station across diverse operational scenarios. The T-type tee induces detachment of the primary flow from the inner wall due to inertial forces, which results in vortex formation and heightened resistance, accompanied by increased energy dissipation. The transition of the rounded inner wall of the dovetail tee results in the reduction of eddy current generation and a smaller separation zone, thus minimizing resistance and energy loss. The maximum static differential pressure between the inlet and outlet of the dovetail tee is reduced by 52.52% compared to that of the T-type tee. In practical engineering applications, the use of dovetail tees leads to a reduction in the height difference for the pipeline by 17.58%, resulting in more uniform and stable flow rates and pressures in the flow field. These improvements contribute to engineering efficiency and environmental sustainability and are particularly evident in the design of LNG filling stations.

STUDY OF THE PROGRAMMABLE ISOKINETIC SAMPLER EFFICIENCY FOR OF ECOLOGICAL DIAGNOSTICS SYSTEMS OF HEAT ENGINES AND BOILER PLANTS

The work is devoted to the solution of the actual scientific and practical task of creating a universal sampling device for systems of environmental diagnostics of heat engines and boiler plants of various purposes. Ensuring the isokinetic mode of sampling from the exhaust pipe (EP) of the engine is a more difficult task than carrying out a similar sampling process in the chimney of the boiler plant, since the exhaust gases of the engines are characterized by fluctuations of static pressures in the HT with an amplitude of up to ±500 Pa, which must be taken into account in the operation of the sampling equipment. In the course of research, based on the analysis of global and domestic experience in the production and use of equipment for environmental certification of internal combustion engines and boiler houses, a programmable isokinetic sampler (ICT) was created, which allows you to take a proportional part of the gas sample from the full flow of exhaust gases in the EP of the power plant with accuracy ±3%. Motorless and motorized test stands have been developed for modeling and research of gas-dynamic processes in the exhaust systems of engines and boiler plants, which provide the possibility of varying the parameters of gas flows - mass flow rate, speed, temperature, static pressure, velocity pressure in the ranges: 15 - 55 g/s; 5...30 m/s, 20...180 °С, 0...2.5 kPa, 10 - 550 Pa, respectively. On the basis of the created test stands, empirical dependences were established to determine the static pressure differences between the ICP and EP pipelines, in which the isokinetic mode of sampling is ensured, from the dynamic pressure of the gas flow in the EP. With the help of these dependencies, SMART control of the programmable ICP is carried out. An experimental development of the programmable ICP was carried out as part of the MT-1 minitunnel during environmental tests of the 1СН12/14 diesel engine in separate modes and according to the ESC cycle established by the UNECE Regulations R-49. The research results confirmed the compliance of the created sampling device with regulatory requirements for its design and the accuracy of determining the sampling coefficient.

Coupling Bionic Design and Numerical Simulation of the Wavy Leading-Edge and Seagull Airfoil of Axial Flow Blade for Air-conditioner

It is essential to maintain the aerodynamic performance of the air-conditioning system meanwhile reducing the noises (including aerodynamic, broadband, and discrete noises), determining the consumer's comfort level. In this work, depending on the coupling of the wavy leading-edge and the seagull airfoil, the aeroacoustics noise and aerodynamic performance of the impellers with the coupling bionic blade were investigated in detail. The results indicate the aerodynamic performance was improved by the coupling bionic optimization. Moreover, the total pressure efficiency (η) of the coupling bionic blade increases by 2.28% in comparison to the original blade. Furthermore, A smaller static differential pressure is observed between the suction and pressure sides, and vortices and backflows from the pressure side to the suction side are hampered, causing a reduction in turbulence noise. Additionally, the broadband noise of the coupling bionic blade decreases by 3.59 dB. Besides, the coupling bionic blade improves the directivity of the sound pressure level, especially in the middle-frequency and low-frequency region, resulting in a decrease of 7.9 dB for the aeroacoustics noise of the coupling bionic blade. What's more, the modal analysis demonstrates the security of the designed coupling bionic blade. In generally, this work provides some inspiration to design axial flow fans with excellent aerodynamic performance and low-noise characteristics.

Study of jet tabs in 2D convergent–divergent nozzle for thrust vectoring in aerial vehicles

PurposeIn this study, 2D density-based SST K-turbulence model with compressibility effect is used to observe the flow separation and shock wave interactions of the flow. The wall static pressure and Mach number differences are also evaluated. This study aims to discuss the aforementioned objectivesDesign/methodology/approachThis study outlines the evaluation of the performance of a 2D convergent–divergent nozzle with various triangular jet tab configurations that can be used for effective thrust vectoring of aerial vehicles.FindingsFrom the study, it is seen that the shadow effect induced by the tab with a height of 30% produces higher oblique wave deflection and higher thrust deflection at the exit nozzle. The numerical calculation concluded that thrust vector efficiency of 30% jet tab is, 0.46%. In the case of 10% jet tab height the thrust vector efficiency is higher, i.e. 1.647%.Research limitations/implications2D study.Practical implicationsThe optimization will open up a new focus in TVC that can be implemented for effective attitude control in aircrafts.Social implicationsUsed in future aircrafts.Originality/valueThe influence of shadowing ratio with different tab heights at different Mach numbers has not been reported in the previous studies. Few of the studies on jet tab are focused on the acoustic studies and not pertaining to the aerodynamic aspects. The multi jet configuration, the combination of location, shapes and other parametric analysis have not been covered in the previous studied.

Benchmarking high performance HVAC Rule-Based controls with advanced intelligent Controllers: A case study in a Multi-Zone system in Modelica

The design, commissioning, and retrofit of heating, ventilation, and air-conditioning (HVAC) control systems are crucially important for energy efficiency. However, designers and control contractors adopt ad-hoc control sequences based on diffused and fragmented information; therefore, most of the existing control sequences are diverse and sub-optimal. ASHRAE Guideline 36 (GDL36), High-performance Sequences of Operation (SOO) for HVAC Systems, was thus developed to provide standardized and high-performance rule-based HVAC control sequences with the main focus on maximizing energy efficiency. However, only limited studies verify the performance of these high-performance rules-based control and most of these studies focus on the single-zone systems. In this Modelica-based simulation study, the high-performance rule-based control sequences from GDL36 were compared to the state-of-the-art intelligent controllers (i.e., optimization-based controller (OBC) and deep reinforcement-learning-based controller (DRLC)) in terms of the energy efficiency and thermal comfort. The performance evaluation was conducted in a medium-sized office building with a multi-zone Variable Air Volume (VAV) cooling system. The OBC and DRLC replaced the GDL36 airside supervisory level control loops. In other words, the optimal supply air temperature (SAT) and static differential pressure (DP) setpoints were determined by the optimization problems in OBC and trained control policy by DRLC. The OBC and DRLC were formulated to minimize the HVAC energy consumption and zone air temperature violation. The OBCs with different control intervals and DRLCs with different hyperparameters in the Proximal Policy Optimization (PPO) algorithm were exploited and fine-tuned. The simulation results show that the GDL36 has a comparable energy performance (within a 3% deviation) with DRLC in the cases with high or mild cooling loads. It also has a comparable energy performance (within a 3% deviation) with OBC in the case of a high cooling load. However, the case with GDL36 consumed 7% more energy in the testing shoulder period. For the thermal comfort metric, the GDL36 has slightly more zone air temperature violations in all testing scenarios compared to the two intelligent controllers. From this case study, we can conclude that the GDL36 has demonstrated its comparable performance in terms of energy efficiency and thermal comfort with the two intelligent controllers. The GDL36 airside SOO is good enough considering the complexity and tuning efforts of the intelligent controllers.

Nonlinear flutter of 2D variable stiffness curvilinear fibers composite laminates by a higher-order shear flexible beam theory with Poisson’s effect

In this work, the nonlinear supersonic panel flutter characteristics of two-dimensional variable stiffness curvilinear fibres based laminated composite panels are studied using a higher-order shear flexible theory represented by sine function coupled with first-order approximation leading to quasi-aerodynamic theory. The structural formation takes care of geometric nonlinearity with von Karman’s assumptions. The beam constitutive equation is modified for the laminated beam with general lay-up by accounting for Poisson’s effect. The nonlinear dynamic equilibrium equations developed by Lagrangian equations of motion are solved using finite element approach in conjunction with the direct iterative solution procedure. For limit cycle oscillation, critical dynamic pressure is predicted iteratively through eigenvalue analysis, thereby identifying the first coalescence of vibrational modes. Also, the flutter behavior of two-dimensional panel under static differential pressure is investigated considering nonlinear static equilibrium position of panel obtained by Newton-Raphson’s iterative approach and then followed by modes coalescence approach. These solution procedures are tested against the results in literature. A thorough numerical investigation is done to show the effect of the curvilinear fiber path orientation, limited cycle amplitude, static differential pressure, panel thickness, panel end condition flexibilities and thermal environment on the nonlinear supersonic panel flutter of two-dimensional variable stiffness laminated panels.

Anomalous intensification of separated flow and heat transfer in one and multiple row deep inclined oval trench dimples on the wall of a narrow channel and on the plate

At the stands of Research Institute of Mechanics at the Moscow State University, we experimentally confirmed the mechanism of anomalous intensification of the separation flow and heat exchange in inclined oval-trench dimples (OTD) on the plate, which was discovered during numerical studies. The measured static pressure differences in single OTD at Re=6.7×104 are in good agreement with the numerical forecasts within the framework of the RANS approach at Re=104.

Differential pressure sensor using flexible piezoelectrics with pyroelectric compensation

Polyvinylidene fluoride (PVDF) is a mechanically tough, low density piezoelectric polymer commercially available as a flexible film that can be conformed to arbitrarily-shaped surfaces using simple adhesive bonding. A fundamental challenge that prevents the implementation of piezoelectric sensors for pressure sensing applications is their inability to measure static or very low frequency signals. Further, due to their large pyroelectric constants, they are limited to measurements where the rate of change in temperature is smaller than the lower cutoff frequency of the system. Under steady flow conditions, the cantilever unimorph possesses the highest sensitivity compared to other conventional configurations such as compression, doubly clamped unimorphs, or diaphragms. However, to preserve the overall noninvasive nature and linearity of the sensor, it is necessary to optimize the geometry and material properties in order to maximize charge output while minimizing deflection. To address these challenges, this work focuses on the development of a cantilever PVDF unimorph for static differential pressure measurement with pyroelectric compensation. A design optimization procedure to maximize the charge sensitivity of a cantilever unimorph is presented and the optimized cantilever is interfaced with a large-time-constant, drift-compensated charge amplifier for near-static pressure measurements. Voltage error due to temperature changes accompanying the input flow is compensated using a compressive mode sensor and an empirical compensation algorithm. Within the investigated range, the sensitivity of the fabricated sensor is 1.05 mV Pa−1 with an average resolution of 10 Pa and 97.3% linearity.

Theoretical analysis for the effect of static pressure differential on aeroelastic stability of flexible panel

The static pressure differentials have been neglected in almost all of theoretical analysis models for panel flutter in the supersonic flow, which are established on the basis of the classic aeroelastic model by Dowell in 1966. However, in actual engineering, flexible panels are still subjected to the static pressure differentials under some circumstances. By using the numerical methods, Dowell et al. found that the static pressure differentials as small as 10−2 psi may significantly alter the flutter boundary. In this paper, a novel strategy for a theoretical analysis model is proposed to study the effect of static pressure differential on aeroelastic stability of flexible panel in the supersonic airflow. We regard the final total displacement of the panel as the superposition of dynamic displacement and static deformation, which is in accord with the actual situation of physicality. The static deformation is obtained by solving the static aeroelastic equation. Using the curve/surface fitting method, the static deformations are described by two approaches with/without considering the interaction between the static deformation and steady aerodynamic loads. And then the static deformation is introduced into the dynamic aeroelastic equations in the form of the stiffness through the nonlinear induced loading. The dynamic aeroelastic equation is solved by using the Galerkin discrete method, which can truncate the partial differential equations into a set of ordinary equations. Lyapunov indirect method is utilized to evaluate the aeroelastic stability of the flexible panel. According to the known expression of static deformation and Routh-Hurwitz criterion, a theoretical solution for the aeroelastic stability boundary under the action of the arbitrary static pressure differentials is derived. The theoretical results show that (1) The static pressure differential can significantly enhance the aeroelastic stability of the flexible panel, which is consistent with the numerical results. (2) Whether the actual coupling between the static deformation and aerodynamic loads is considered or not, the stability boundaries obtained are quite different. (3) The increase of the stiffness of structure induced by the static deformation can increase the critical flutter dynamic pressures, but it is not the dominant factor to lead to such a remarkable improvement of the stability of the flexible panel under the action of the static pressure differential. The actual coupling between the static deformation and aerodynamic loads plays a significant role in substantially improving the aeroelastic stability of the flexible panel.

Experimental measurements of gas pressure drop of packed pebble beds

The nearly spherical shaped ceramic pebble beds in the breeder blanket of the future fusion reactor are purged by low-pressure gas to channelize the produced tritium fuel into the tritium extraction system. The required pumping power for the flowing gas in pebble beds can be estimated using the pressure drop across the pebble beds. The aim of this work is to measure the gas pressure drop experimentally across packed pebble beds as a function of pebble sizes, pebble shapes, pebble materials, and gas velocity. The pebble beds are packed in a cylindrical-shaped stainless steel container with an inner diameter of 24 mm and a length of 130 mm. The various experiments have been performed on stainless steel spheres (Diameter: 1 mm, 2 mm, 3 mm, and 4 mm), alumina pebbles (Mean diameter: 1 mm and 1.5 mm), and lithium meta-titanate pebbles (Mean diameter: 1 mm and 1.3 mm). The gas flow has been controlled and measured using a digital mass flow controller. The static differential pressure across the pebble beds has been monitored by a differential pressure transducer. The pressure drop significantly increases with a decrease in the diameter of pebbles/spheres and an increase in the packing fraction of the bed. The material type does not affect the results which are too obvious for the fixed pebble bed which is considered in these experiments. The obtained experimental results of gas pressure drop have been compared and agreed well with the prediction of the Ergun’s correlation.

Instability measurement for plate-type fuels subjected to narrow-parallel flow

Plate-type fuel assemblies are utilized in many research reactors. Some are open-loop, pool-type reactors, but others are pressurized reactors with high coolant flow rates. Parallel flows between the fuel plates can make these plates unstable. Several studies in the early 60s reported that the plates could lose their stability through a static type of instability. In accordance with studies in the 70s, however, the type of instability, whether static or dynamic, may depend on the boundary conditions. In this study, we present experimental observations of the instability of a fuel plate subjected to a narrow-axial flow between several different fuel plates. We sought to measure and compare the critical flow velocity with predictions according to Miller’s theory, which is generally used during the design of a plate-type fuel. For this experiment, we installed strain gages on a target plate (instrumented plate) positioned at the center of five simulated plates to reflect the fluid interaction in the narrow gaps between the plates. Pressure sensors were also installed to measure the static pressure differences between two channels adjacent to the target plate in an effort to identify the moment of instability. We observed that the stability of the target plate is lost due to a static type of instability at a flow velocity of 16.4 m/s, slightly lower than the flow velocity predicted using Miller’s equation for a fixed–fixed boundary condition.

Field evaluation of the performance of fan coil units with permanent split capacitor fan motors

The purpose of this study was to provide in situ field data on fan/motor efficiency and fan static pressure differentials for the fan/motor combinations used in fan coil units. Measurements were made on 321 fan coil units with permanent split capacitor motors in three university residence halls and one commercial building. Data included manufacturer, model number, airflow, static pressures at the inlet and outlet of the fan coil unit, voltage, current, and external static pressure across the unit. All units had data on static pressure differential across the fans and most had external static pressure measurements across the fan coil units. Over 97% of the units operated with external static pressure differentials at or below 0.4 in. w.g. (100 Pa). Over 78% of the units were below 0.2 in. w.g. (50 Pa). A correlation for fan/motor static efficiency versus fan static pressure differential was developed. The analysis provided estimates of both fan/motor static efficiency and fan static pressure differential that should provide users of building simulations programs with a reasonable estimate of these variables when simulating fan coil units. The data showed that fan efficacy was independent of either fan static pressure differential or external static pressure.

Using CFD simulations to develop an upward airflow displacement ventilation system for manure-belt layer houses to improve the indoor environment

Heat stress and disease outbreak result in significant losses in large-scale egg productions. New ventilation systems are needed for large-scale layer production facilities to provide safe and uniform indoor environment, especially in the changing climate of global warming. This study developed a new ventilation system, upward airflow displacement ventilation (UADV) system, which allows fresh air to enter a layer house through air ducts located at the bottom of the cages, move upward by thermal buoyancy caused by hens and static pressure differences caused by exhaust fans, and ultimately exit the house through the fans installed on the roof. The performance of the UADV system was evaluated in comparison with a typical tunnel ventilation (TV) system in terms of air-exchange effectiveness, thermal environment, and airborne pathogen dispersal in both summer and winter using a validated Computational Fluid Dynamics (CFD) model. The results showed that the UADV system resulted in 46%–129% greater air-exchange effectiveness within the cages and provided a more homogeneous thermal environment with 9.4% less heat stress in summer and 68% less cold stress in winter compared with the TV system. In addition, transport of pathogens was largely inhibited in the UADV system compared with the TV system due to upward airflow and minimum air mixing across the cages. When coupled with sensible cooling of supply air, UADV system can further improve the thermal environment with a much lower ventilation rate under extremely hot and humid weather conditions. However, higher ventilation rates were more effective for reducing potential pathogen dispersal.

Seed Cotton Mass Flow Measurement in the Gin

Abstract. Seed cotton mass flow measurement is necessary for the development of improved gin process control systems that can increase gin efficiency and improve fiber quality. Previous studies led to the development of a seed cotton mass flow rate sensor based on the static pressure drop across the blowbox, which primarily results from acceleration of the seed cotton. The initial sensor did not perform satisfactorily in a gin, and modifications were made to account for air leakage through the rotary valve at the blowbox and the temperature drop occurring due to heat exchange between the seed cotton and air. Mass flow rate was predicted based on the static pressure differences across the blowbox and rotary valve, the air velocity and density at the blowbox inlet, the air density in the blowbox, and the ambient air density. The first- and second-stage seed cotton cleaning and drying systems of the commercial-scale gin at the Cotton Ginning Research Unit were instrumented to test the improved model. Air velocity, cultivar, dryer temperature, and seed cotton feed rate were varied to determine their effects on model accuracy. Mean absolute percentage errors in predicting mass flow rate were 3.89% and 2.85% for the first- and second-stage systems, respectively; however, dryer temperature had a significant effect on the regression coefficients. An additional regression parameter was added to the model to better estimate the average blowbox density, reducing the mean absolute percentage error to 2.5% for both systems and eliminating the effect of dryer temperature on the regression coefficients. Keywords: Cotton, Ginning, Mass flow, Pneumatic conveying, Pressure.

Mass flowrate measurement using the swirl motion in circular conduits

In this paper, a method of mass flow measurement was presented based on swirl motion motivated by specific shapes of swirlers. The measuring principle of the method has been proposed by theoretical analysis and has been verified by experiment and numerical simulation. The relationship between the average axial velocity (vz̅) and the static differential pressure between the pipe wall and pipe center of a cross section downstream of a swirler (∆P) was especially emphasized. It shows that vz̅ is in direct proportion to ∆P when certain fluid flows through a specific swirler. For a certain cross section downstream of a swirler, there exist two places with different radius and different corresponding tangential average velocities, whereas with the same values of tangential average acceleration. The RSM was used as the turbulence model in simulation. Compared with the experiments, the relative errors of the flow coefficient (α) are 1.25% and 4.74% for the cross sections of 2.7D and 11.8D downstream of the swirler, respectively, which are within the scope of acceptable. In addition, we conducted the numerical simulation work of the influences of swirler on α. The results show that the bigger the angle between each slice and pipe cross section and less numbers of slices will achieve less ∆P and bigger α. This method may provide an alternative way to mass flow measurement which is easier to be standardized than other nonstandard differential pressure flowmeters.

An AlN cantilever for a wake-up switch triggered by air pressure change

This research reports an AlN cantilever with an air chamber for a wake-up switch triggered by air pressure change. The proposed sensor is designed to fulfil both high sensitivity and low power consumption. By combining an air chamber to the one side of the AlN cantilever surface, the barometric pressure change generates a piezoelectric voltage. Thus, a wake-up switch triggered by air pressure change can be achieved using an AlN cantilever. The size of the fabricated AlN cantilever was 2000 μm × 1000 μm × 2 μm. The sensitivity to static differential pressure was 11.5 mV/Pa at the range of −20 Pa to 20 Pa. We evaluated the response of the sensor, which was composed of the AlN cantilever and the chamber of 60 ml in volume, when air pressure change was applied. The output voltage increased with increasing the applied air pressure change. It was observed that the maximum output voltage of 50 mV was generated when the air pressure change was 13 Pa.

A Dome Shaped PVDF Loudspeaker Model

An analytical model is developed that describes the behavior of a dome-shaped piezoelectric loudspeaker. The loudspeaker consists of a PVDF circular membrane coupled with a rear cylindrical cavity. The dome shape is obtained by means of a static differential pressure held between the two faces of the membrane. The theoretical description of the transducer's behavior is conducted in two steps. In the first step, the static behavior of the membrane is studied in order to obtain the profile of the membrane when submitted to a static differential pressure. In the second step, the dynamic behavior of the membrane is studied. Finally, the theoretical results obtained are compared with experiments in order to evaluate the accuracy of the model.