Actual Mass Flow Research Articles

Modeling the Discharge Rate of a Screw Conveyor Considering Hopper–Conveyor Coupling Parameters

Developing a flow rate model for the screw feeder and optimizing discharge performance are crucial for achieving automated intelligent precision feeding. This study constructs a mass flow rate model for screw conveyors, considering the coupled structural parameters of the hopper and screw conveyor. The model is developed using single-factor tests and central composite design (CCD) response surface tests and is validated through actual discharge tests. Results indicate that the discharge rate in the hopper–screw conveyor system is primarily influenced by the screw conveyor itself. Among the structural parameters, the hopper inclination angle and the hopper discharge opening length significantly affect the filling coefficient. Validation tests show an average error of 6.8% between the predicted and simulated mass flow rates and 5.0% with the actual mass flow rate, demonstrating the model’s high precision and accuracy.

Fluid–Thermal–Structure Interaction of Hypersonic Inlets Under Different Aspect Ratios

It is crucial to consider the fluid–thermal–structural interaction (FTSI) in designing the scramjet inlet for sustained hypersonic flight. To understand the aerothermal and aeroelastic responses of the planar hypersonic inlets under different flight Mach numbers and aspect ratios, a three-dimensional FTSI framework was developed and validated. After that, the FTSI characteristics under different flight Mach numbers and aspect ratios were investigated. The result reveals that the most obvious horizontal displacement happens at the cowl lip leading edge, whereas the maximum vertical displacement takes place at the compression-ramp leading edge. The FTSI improves the capture area and generates an additional compression angle due to the different thermal expansions between the windward and leeward panels. The thermal expansion in the spanwise direction causes the cowl lip to hump into an arc, and the maximum height happens at the midplane. The effects of FTSI on the inlet flowfield, the mass flow rate, and the total pressure ratio under different flight Mach numbers and aspect ratios were obtained. Overall, the FTSI can improve the contraction ratio, the actual mass flow rate, and the pressure ratio while causing the total pressure ratio to decrease by up to 14.64%.

Leakage analysis of the metal-to-metal contact check valve for a cryogenic sorption compressor

A check valve which is a critical component for cryogenic sorption compressor, has been developed previously by several researches. Its leakage rate was phenomenologically explained by the model of Poiseuille flow with the effect of pressure difference or temperature. This paper specifically investigates the leakage rate of the metal-to-metal check valve at 20 K, 77 K and 294 K in the situation of the back pressure from 150 kPa to 1,450 kPa. The leakage flow phenomenon is analyzed in more detail at various temperature, pressure difference and flow regime. Since Poiseuille flow which was adopted by previous researches cannot comprehensively reflect the effect of temperature and the pressure difference, the transition flow model has been subsequently employed to predict the leakage rate at 20 K. The leakage rate at 20 K is well predicted by using the 77 K and 294 K results with maximum and minimum approximation error of 22 % and 3.5 %, respectively. Uncertainty analysis is conducted to ensure the reliability of the prediction results. Furthermore, the allowable leakage rate of the check valve according to the ratio of the actual and ideal mass flow rates of the sorption compressor are derived.

Deep Learning Model for Prediction of Air Mass Deviation Faults

Major Systems of an internal combustion Engine are Air System, Fuel system, and Exhaust system. Any malfunction in these systems increases emissions. OBD legislation mandates to monitor these systems for any faults and appropriate action should be taken in case of the any faults which increase vehicle emissions. The idea of the paper is to find the Air mass flow deviation faults using datamining and machine learning based approach. Detection of fault is classifying whether system is faulty or not. Objective is to create a deep learning model using the available vehicle data to classify the system for a fault. Three main inputs for the Air Mass flow in an internal combustion Engine are1) Fresh Air which measure using Mass Air Flow sensor2) Low Pressure EGR3) High Pressure EGRDuring vehicle lifetime, due to different real vehicle operating conditions and environmental conditions, deviation in the set point of air mass flow and actual mass flow are possible to an extent, which can affect vehicle emissions. Deviation in the Air Mass flow can be caused by intake Air mass, LP-EGR, HP-EGR. The Aim of the project is to create the deep learning model for Air Mass Flow Hi and Low faults using the available data, and associate the fault to the component in the Intake Air System.

Solar Field Output Temperature Optimization Using a MILP Algorithm and a 0D Model in the Case of a Hybrid Concentrated Solar Thermal Power Plant for SHIP Applications

Using solar power for industrial process heat is an increasing trend to fight against climate change thanks to renewable heat. Process heat demand and solar flux can both present intermittency issues in industrial systems, therefore solar systems with storage introduce a degree of freedom on which optimization, on a mathematical basis, can be performed. As the efficiency of solar thermal receivers varies as a function of temperature and solar flux, it seems natural to consider an optimization on the operating temperature of the solar field. In this paper, a Mixed Integer Linear Programming (MILP) algorithm is developed to optimize the operating temperature in a system consisting of a concentrated solar thermal field with storage, hybridized with a boiler. The MILP algorithm optimizes the control trajectory on a time horizon of 48 h in order to minimize boiler use. Objective function corresponds to the boiler use, for completion of the heat from the solar field, whereas the linear constraints are a simplified representation of the system. The solar field mass flow rate is the optimization variable which is directly linked to the outlet temperature of the solar field. The control trajectory consists of the solar field mass flow rate and outlet temperature, along with the auxiliary mass flow rate going directly to the boiler. The control trajectory is then injected in a 0D model of the plant which performs more detailed calculations. For the purpose of the study, a Linear Fresnel system is investigated, with generic heat demand curves and constant temperature demand. The value of the developed algorithm is compared with two other control approaches: one operating at the nominal solar field output temperature, and the other one operating at the actual demand mass flow rate. Finally, a case study and a sensitivity analysis are presented. The MILP’s control shows to be more performant, up to a relative increase of the annual solar fraction of 4% at 350 °C process temperature. Novelty of this work resides in the MILP optimization of temperature levels presenting high non-linearities, applied to a solar thermal system with storage for process heat applications.

A New Approach of Dedusting for IGCC by a Two-Stage Moving Granular Bed Filter

We propose a dust removal technology in which a two-stage moving granular bed filter was employed using coarse and fine filtering granules. The pressure drop, collection efficiency, and dust particulate size distributions were investigated using various mass flow rates for coarse and fine granules at room temperature. In addition, the ratio of mass consumption was used to reveal the actual mass flow. The ratio of mass consumption influenced the pressure drop, collection efficiency, and dust particulate size distributions. Particulates larger than 1.775 μm were removed by the filter. Our results showed that a mass flow of 330 g/min for coarse granules and a mass flow of 1100 g/min for fine granules provided optimal collection efficiency and particulate size distribution. The proposed design can aid the development of high-temperature systems in power plants.

АЛГОРИТМ КОМПЛЕКСНОЙ ДИАГНОСТИКИ ТЕХНИЧЕСКОГО СОСТОЯНИЯ СТРОИТЕЛЬНЫХ КОНСТРУКЦИЙ ПО АНАЛИЗУ ТЕРМОГРАММ

the algorithm of complex diagnostics of a technical condition of building constructions and structures on the analysis of thermograms is offered. An attempt is made to systematize and logically build a sequence of stages of energy inspection of heat-consuming and heat-generating construction projects and their structural elements. The presented algorithm includes the main stages performed in such surveys. It differs from the known technologies of energy monitoring of buildings and structures by the presence of two additional stages, which are an integral part of any energy survey: determination of the relative surface humidity of building structures and the actual mass flow of coolant through the heating device for the analysis of thermal images. The implementation of energy (thermal imaging) and technical inspections according to the presented structural scheme requires not only the presence of appropriate instrumentation and measurement base, but also the involvement of highly qualified specialists (civil engineers, thermal power engineers, thermal physicists, operators-thermographers, etc.).

Flow Analysis and Theoretical Design of Diesel Engine Exhaust Port

Exhaust port is an important part of a diesel engine which affects the combustion and emission. It is important to have a good design for exhaust port. In this paper, the calculation formula of the optimal area ratio (Kopt) of outlet and inlet of exhaust port was derived. The formula shows that Kopt is only determined by relative pressure difference (RPD). Then influence of the area ratio (K) of outlet and inlet on flow capacity of exhaust port and the trend of Kopt with relative pressure difference were studied numerically to verify the validity and applicability of the formula. The numerical results shows that the mass flow rate increases first and then keeps constant with the increase of K at the same RPD. Kopt exists and decreases first and then keeps constant with the increase of RPD. The numerical trend is consistent with theoretical trend and the errors between maximum mass flow rates of numerical results and actual mass flow rates at theoretical optimal area ratios are all less than 5% meeting engineering accuracy. It is indicated that the derived formula is correct and applicable. When an exhaust port is designed, the outlet area can be estimated by this formula.

Thermal Method for Non-Destructive Control of Actual Coolant Mass Flow through a Heating Device

The studies show that expenses for heating buildings and structures account for more than 60% of total utility costs in the Russian Federation. Therefore, the issues on energy and resource conservation and improving the energy efficiency of construction projects for various purposes are relevant and priority. Infrared thermography is actively used during examination of thermomechanical equipment, building structures, external and internal engineering systems and their elements. Heat monitoring makes it possible to avoid significant costs for dismantling of controlled objects and to localize the thermal defects found during the inspection stage, thereby reducing costs of repair works. The article considers and analyzes the existing options for the quantitative analysis of thermograms. The authors propose a new method for quantitative processing of thermograms, aimed at assessing the operation of heating devices in heating systems of buildings and structures. The essence of thermal non-destructive testing technique is to determine the actual mass flow rate of coolant through the heating device.

Algorithm for Integrated Non-Destructive Diagnostics of Technical Condition of Structures of Buildings and Constructions Using the Thermogram Analysis

An algorithm for integrated non-destructive diagnostics of technical condition of structures of buildings and constructions using the temperature field analysis is proposed. An attempt is made to systematize, characterize and build a logical sequence of stages for energy inspection of heat-consuming and heat-generating construction objects and their structural elements. The presented algorithm differs from the well-known technologies for energy monitoring of buildings and structures by the presence of two additional steps, which are an integrated part of any energy examination: determination of the relative surface humidity of building structures and the actual mass flow of coolant through a heating system using qualitative and quantitative assessment of thermal images. The implementation of energy (thermal imaging) and technical examinations according to the presented structural scheme requires appropriate equipment, as well as involvement of highly qualified specialists (civil engineers, thermal power engineers, thermal physicists, thermal imaging operators, etc.).

An ingenious characterization of reaction network using sub-network reconstruction

Reaction network model is essential for reactor simulation and kinetic profiling of a complex process. Comprehensive and valid proofs of network mechanism are usually lacking among experimental and simulation studies of complicated reaction process, such as ethylene furnace co-cracking. In this paper, a self-developed Ethylene cracker Simulation and Optimization System (EcSOS) software is applied for co-cracking process numerical simulation and an ingenious characterization method of reaction network is proposed for visualization and deep profiling of the radical reaction network. An effective sub-network reconstruction process is implemented by connecting the substance nodes using actual mass flow and refining key interactions. The product yield evolving trend in simulation and its reason was successfully explained by the reaction network analysis results. The radical reaction mechanism changing obtained by reaction backtracking was systematically sorted out and summarized.

Signal Analysis of Supersonic Vapor Condensation in Nozzle Sensor Using Distributed Transient Pressure Probes

The amplitude–frequency characteristics of self-excited oscillating pressure in nozzle condensation dominate the actual flow field and mass flow rate, which affect the measurement accuracy of the sonic nozzle for the moist gas. In order to estimate this effect and improve the measurement accuracy, the complex supersonic vapor nozzle condensation with different nozzle geometries was investigated. First, the raw signals of the time-averaged and transient oscillating pressure during the condensation occurs in the nozzle were acquired, by using a multiparameter adjustable humidification apparatus, two nozzle sensors with distributed pressure probes and a 10th order low-pass hardware filter. Then, these raw signals were decomposed and reconstructed to further improve the filtering result, by using discrete wavelet transforms with the Db5 wavelet bases. Finally, the accurate amplitude–frequency characteristics of the transient pressure signals were extracted and analyzed by fast Fourier transform and the ratio correction method. It found that the experimental frequencies are mainly dependent on the curvature of nozzle wall and mass fraction of water vapor, which is also compared with a semiempirical formula derived from the experiments of 2-D symmetric rectangular nozzle. The results showed that this formula has a significant deviation from the experimental results of 3-D toroidal nozzles, which needs to be investigated further. All the research is contributed to further analyze the effect of condensation on the actual mass flow of the sonic nozzle.

A novel quasi-one-dimensional model for performance estimation of a Vaporizing Liquid Microthruster

The present work aims to propose a novel quasi-one-dimensional model for the performance estimation of a Vaporizing Liquid Microthruster (VLM). The analytical model was applied to the analysis of a MEMS-based VLM composed of a rectangular inlet chamber, a set of parallel microchannels as heating chamber, and a planar convergent–divergent micronozzle. It combines a steady-state boiling model for the analysis of the heater with a real nozzle flow model for the evaluation of actual thrust force and specific impulse, based on iterative procedure aiming at the convergence of the actual mass flow rate and the heat flux. For the purpose, a set of semi-empirical formulas found among both theoretical and experimental scientific works have been introduced for the estimation of the critical heat flux condition and the local heat transfer coefficient. In addition, the real nozzle flow model predicts the performance and the viscous losses due to the boundary layer growth inside the micronozzle. The last ones are estimated by introducing analytical expressions for the discharge coefficient and the Isp-efficiency into the isentropic nozzle flow theory. The resulting performance predictions of the 1D model referred to the on-design operating conditions. They well agreed with the experimental data, with a maximum estimated error of 7.3% on the thrust and the specific impulse. Furthermore, the analytical model of the micronozzle predicted a reduction of the mass flow rate up to about 8%, as well as thrust losses up to 15% due to the contraction of the cross sectional area.In addition, 2D and 3D computational fluid dynamics (CFD) simulations were performed in order to enforce the analysis of the viscous effects. Predictions of 2D computations overestimated the performances of the microthruster with respect to experiments, up to about 19% of the thrust and 20% of the specific impulse. On the other hand, the 3D predicted thrust approached to the experimental one with an error of about 9.2% below. In addition, a severe reduction of jet thrust in favor of the pressure thrust was observed at the nozzle exit. Furthermore, 3D computations pointed out the influence of the micronozzle depth on the boundary layer growth and the viscous losses. In particular, they revealed the establishment of the nozzle blockage and the thermal chocking of the supersonic flow owing to the subsequent viscous heating.

Real-time acoustic emission monitoring of powder mass flow rate for directed energy deposition

In order to ensure a reliable and repeatable additive manufacturing process, the material delivery rate in the directed energy deposition (DED) process requires in situ monitoring and control. This paper demonstrates acoustic emission (AE) sensing as a method of monitoring the flow of powder feedstock in a powder fed DED process. With minimal calibration, this signal closely correlates to the actual mass flow rate. This article describes the fabricated mass flow monitoring system, documents various conditions in which the actual flow rate deviates from its set value, and details situations that highlight the system’s utility. While AE mass flow monitoring is not free of concerns, its features make it an attractive measurement technique in the powder-fed DED process. The work presented here highlights the results obtained and illustrates that accurate monitoring of powder flow in real-time regardless of environmental conditions within the build chamber is possible.

Experimental procedure for the characterization of turbocharger’s waste-gate discharge coefficient

Nowadays, the turbocharger has become one of the key components for automotive spark-ignition engine improvements (fed with both liquid and gaseous fuels), as a support for the boosting and downsizing concept to reduce fuel consumption and exhaust emission. In gasoline engines, the usage of the waste-gate valve typically regulates the maximum boost pressure in the turbocharger system, to protect the engine and the turbocharger at high engine speeds. To improve the transient response at low engine speeds, two-stage turbocharger is widely used. Two-stage systems are composed of several valves to regulate the flow to control the boosting of the system. Like a bypass valve between the turbines, a check valve is present between the compressor and a waste-gate valve for the low-pressure turbines. This article deals with a methodology for characterizing the discharge coefficient of an electronic waste-gate valve in the turbocharger. To estimate the gas flow over the same in one-dimensional models, an empirical model is correlated and validated. For this, a constant-stream experimental work has been carried out on a test rig at different valve position openings, with high turbine inlet temperatures. Finally, an optimal map of discharge coefficient has been drawn out through interpolation method, which can integrate into the full one-dimensional turbocharged engine model system, to calculate the actual mass flow through the waste-gate valve.

Towards an optimal aiming for molten salt power towers

Finding a suitable aiming strategy for receivers of power towers can be challenging, especially for receivers using molten salt as heat transfer fluid as the allowable flux density decreases dramatically with increasing salt temperature. In this paper a very fast, steady-state model for the molten salt receiver is presented. This model is combined with a ray-tracing software and a metaheuristic optimization procedure. The thermal model is used to calculate the actual temperature and mass flow in the receiver which are then used to calculate the operational limits for the flux density. It is demonstrated that such an optimized aiming strategy can outperform a parameter based aiming strategies by more than 2%.

Development of a numerical correlation for the discharge coefficient of round inclined holes with low crossflow

Abstract The estimation of the discharge coefficient is of paramount importance in gas turbine design as this parameter affects the actual mass flow rate through secondary air and cooling systems. The lack of confidence in the estimation of its value may entail a reduction in the engine performance as well as lifespan. The scope of this work is therefore still an object of study in the scientific community, mostly due to the complexity and the variety of phenomena involved. In an effort to provide a general characterization of the aerodynamic losses across round orifices, an extended numerical campaign was carried out to develop a correlation for the discharge coefficient. The investigation was focused on round, inclined holes at isothermal conditions, with limited crossflow on both mainstream and coolant sides. Exploiting CFD simulations validated against a literature test case, a Design of Experiments (DoE) was performed to assess the influence of length-to-diameter ratio (L/d), inclination angle with respect to the crossflow direction (α) and pressure ratio (β). The large amount of data obtained were then correlated in order to provide an expression capable of predicting the discharge coefficient. The correlation is valid for round holes ( α = 20 ∘ − 90 ∘ , L / d = 1 − 10 , β = 1.01 − 2.0 ) with low crossflow on both mainstream and coolant sides ( M a m = M a c = 0.02 ). allowing to reproduce the CFD data set with a mean absolute error of 3.44% and a standard deviation of 1.81%.

Comparison of the Models of the Air Gauge Static Characteristics

Abstract In the article, the authors analyze and discuss several models used to the calculation of air gauge characteristics. The model based on the actual mass flow (which is smaller than the theoretical one) was proposed, too. Calculations have been performed with a dedicated software with the second critical parameters included. The air gauge static characteristics calculated with 6 different models were compared with the experimental data. It appeared that the second critical parameters model (SCP) provided the characteristics close to the experimental ones, with an error of ca. 3% within the air gauge measuring range.

Gasification of high-ash Indian coal in bubbling fluidized bed using air and steam – An experimental study

In this experimental study, gasification characteristics of Indian coals having high ash content (>35%) in a bubbling fluidized bed reactor, using air and steam as the gasification agents under atmospheric pressure, are presented. The thermal power output of the gasification device has been varied in the range of 80–100kW. The ratio of the actual mass flow rate of air supplied to the stoichiometric air mass flow rate (required for complete combustion) has been varied in the range of 0.25–0.35. The ratio of mass flow rate of steam to that of coal has been varied from 0.15 to 0.25. Effects of air and steam flow rates on the calorific value of product gas, carbon conversion and cold gas efficiency have been studied in detail. For high-ash Indian coals, supply of steam produces positive effect as all the metrics such as calorific value of product gas, carbon conversion and cold gas efficiency increases with increase in the steam supply rate.

Potential Use of BEST® Sediment Trap in Splash - Saltation Transport Process by Simultaneous Wind and Rain Tests.

The research on wind-driven rain (WDR) transport process of the splash-saltation has increased over the last twenty years as wind tunnel experimental studies provide new insights into the mechanisms of simultaneous wind and rain (WDR) transport. The present study was conducted to investigate the efficiency of the BEST® sediment traps in catching the sand particles transported through the splash-saltation process under WDR conditions. Experiments were conducted in a wind tunnel rainfall simulator facility with water sprayed through sprinkler nozzles and free-flowing wind at different velocities to simulate the WDR conditions. Not only for vertical sediment distribution, but a series of experimental tests for horizontal distribution of sediments was also performed using BEST® collectors to obtain the actual total sediment mass flow by the splash-saltation in the center of the wind tunnel test section. Total mass transport (kg m-2) were estimated by analytically integrating the exponential functional relationship using the measured sediment amounts at the set trap heights for every run. Results revealed the integrated efficiency of the BEST® traps at 6, 9, 12 and 15 m s-1 wind velocities under 55.8, 50.5, 55.0 and 50.5 mm h-1 rain intensities were, respectively, 83, 106, 105, and 102%. Results as well showed that the efficiencies of BEST® did not change much as compared with those under rainless wind condition.