MATHEMATICAL MODELING OF THERMAL POWER PLANT'S BOILER AIR-GAS FLOW PATH REGULATION MODES

The National Renewable Energy Laboratory (NREL) and Plug Power Inc. have been working together to develop fuel cell modeling processes to rapidly assess critical design parameters and evaluate the effects of variation on performance. This paper describes a methodology for investigating key design parameters affecting the thermal performance of a high temperature, polybenzimidazole (PBI)-based fuel cell stack. Nonuniform temperature distributions within the fuel cell stack may cause degraded performance, induce thermo-mechanical stresses, and be a source of reduced stack durability. The three-dimensional (3-D) model developed for this project includes coupled thermal/flow finite element analysis (FEA) of a multi-cell stack integrated with an electrochemical model to determine internal heat generation rates. Sensitivity and optimization algorithms were used to examine the design and derive the best choice of the design parameters. Initial results showed how classic design-of-experiment (DOE) techniques integrated with the model were used to define a response surface and perform sensitivity studies on heat generation rates, fluid flow, bipolar plate channel geometry, fluid properties, and plate thermal material properties. Probabilistic design methods were used to assess the robustness of the design in response to variations in load conditions. The thermal model was also used to develop an alternative coolant flow-path design that yields improved thermal performance. Results from this analysis were recently incorporated into the latest Plug Power coolant flow-path design. This paper presents an evaluation of the effect of variation on key design parameters such as coolant and gas flow rates and addresses uncertainty in material thermal properties.

Download Full-text

Use of Digital Twins for Mathematical Modeling of Ultrasonic Cutting of Titanium Blanks

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1037.369 ◽

2021 ◽

Vol 1037 ◽

pp. 369-376

Author(s):

Maxim Ilyushkin ◽

Kirill Savelev ◽

Oleg Krupennikov ◽

Evgeniy S. Kiselev

Keyword(s):

Mathematical Modeling ◽

Thermal Power ◽

Experimental Studies ◽

Ultrasonic Field ◽

Design Parameters ◽

Digital Twins ◽

Machine Parts ◽

Cutting Processes ◽

Stock Removal ◽

Processing Zone

The paper presents the results of numerical experimental studies of cutting titanium blanks using mathematical modeling programs, which make it possible to completely repeat technological processes in a computer (digital twin). The LS-DYNA product was used as a program to simulate the process of stock removal from titanium blank. It has been established that the use of this method adequately describes the cutting processes, including with the introduction of the energy of an ultrasonic field into the processing zone, can significantly reduce the duration of experimental research and evaluate the influence of the elements of the cutting mode and design parameters of the tool on the thermal power aspects of the formation of new surfaces of machine parts.

Download Full-text

MATHEMATICAL MODELING OF ACOUSTIC IMPACT ON GAS FLOW IN VORTEX-ACOUSTIC DISPERSANT

Bulletin of Belgorod State Technological University named after V G Shukhov ◽

10.12737/article_58e6133828b832.29820023 ◽

2017 ◽

Vol 2 (4) ◽

pp. 123-126

Author(s):

Горлов ◽

Aleksandr Gorlov ◽

Савотченко ◽

Sergey Savotchenko ◽

Петрашев ◽

...

Keyword(s):

Mathematical Modeling ◽

Gas Flow ◽

Acoustic Impact

Download Full-text

Impact of Heterogeneity on the Transient Gas Flow Process in Tight Rock

Energies ◽

10.3390/en12183559 ◽

2019 ◽

Vol 12 (18) ◽

pp. 3559 ◽

Cited By ~ 1

Author(s):

Jia ◽

Tsau ◽

Barati ◽

Zhang

Keyword(s):

History Matching ◽

Gas Flow ◽

Preferential Flow ◽

Early Stage ◽

Ideal Gas ◽

Flow Path ◽

Flow Process ◽

The Core ◽

Porosity And Permeability ◽

Preferential Flow Path

There exits a great challenge to evaluate the flow properties of tight porous media even at the core scale. A pulse-decay experiment is routinely used to measure the petrophysical properties of tight cores including permeability and porosity. In this study, 5 sets of pulse-decay experiments are performed on a tight heterogeneous core by flowing nitrogen in the forward and backward directions under different pressures under pore pressures approximately from 100 psi to 300 psi. Permeability values from history matching are from about 300 nD to 600 nD which shows a good linear relationship with the inverse of pore pressure. A preferential flow path is found even when the microcrack is absent. The preferential path causes different porosity values using differential initial upstream and downstream pressure. In addition, the porosity values calculated based on the forward and backward flow directions are also different, and the values are about 1.0% and 2.3%, respectively, which is the primary novelty of this study. The core heterogeneity effect significantly affects the very early stage of pressure responses in both the upstream and downstream but the permeability values are very close in the late-stage experiment. We proposed that that there are two reasons for the preferential flow path: the Joule–Thomson effect for non-ideal gas and the core heterogeneity effect. Based on the finding of this study, we suggest that very early pressure response in a pulse-decay experiment should be closely examined to identify the preferential flow path, and failure to identify the preferential flow path leads to significant porosity and permeability underestimation.

Download Full-text

Computational Studies for the Exhausted Flue Gas

Volume 3: Design and Analysis ◽

10.1115/pvp2005-71024 ◽

2005 ◽

Author(s):

V. C. S. Ferreira ◽

C. S. S. M. Cordeiro ◽

J. W. Kaehler

Keyword(s):

Flue Gas ◽

Gas Flow ◽

Simulation Analysis ◽

Thermal Power ◽

Computational Studies ◽

Rio Grande Do Sul ◽

High Concentration ◽

Abrasive Particles ◽

Set Up ◽

Technical Solutions

Pulverized coal with low average heating, producing ashes with high percentage of silica, is fired inside the furnaces of a Thermal Power Plant (TPP) of Candiota, State of Rio Grande do Sul, Brazil. The produced hot flue gas heats the water of the ECONOMIZER 01 (ECO 01) placed inside the exhausted duct. Distorted velocity profile at inlet of ECO 01 and high concentration of abrasive particles of flue gas cause drastic erosion. So intensive has been the abrasive action that some well-identified tubes end up collapsing. The unpredictable fail has caused many non-scheduled stops of the TPP. A study focused on the reduction this effect, was set up years ago. The paper shows part of this study end present results, obtained from the numerical simulation analysis of the flue gas flow. Some technical solutions are suggested to reduce the erosion of tubes providing that avoiding it showed be impossible.

Download Full-text

Utility of gas inlet pressure monitoring in extracorporeal membrane oxygenation

The International Journal of Artificial Organs ◽

10.1177/0391398820962122 ◽

2020 ◽

pp. 039139882096212

Author(s):

Yuki Nakamura ◽

Takafumi Nakakita ◽

Kazuhiko Yamamoto ◽

Aki Kamada ◽

Shinichi Iguchi ◽

...

Keyword(s):

Gas Flow ◽

Sodium Dodecyl ◽

Significant Negative Correlation ◽

Solution Concentration ◽

Flow Path ◽

Inlet Pressure ◽

Plasma Leakage ◽

Pressure Changes ◽

The Relationship ◽

Reduced Surface

Purpose: Purpose: Condensation that clogs the hollow fibers of the oxygenation and accumulation of plasma leaks reduces oxygenated lung capacity. In this study, artificial We evaluated whether monitoring changes in lung gas inlet pressure was a way to predict these complications. Methods: Changes in gas inlet pressure and oxygenation capacity of three different prostheses (BIOCUBE6000, EXCELUNG PRIME, and Capiox-LX) Evaluated the relationship. When simulating plasma leakage using BIOCUBE6000, sodium dodecyl sulfate (SDS) (1%, 0.1%, A solution of 0.01%, and RO water) reduced surface tension. During 120 minutes of circulation, changes in gas inlet pressure and leakage from the membrane into the gas flow path The amount of fluid was measured. Results: There was a significant negative correlation between the gas inlet pressure changes and the oxygenation capacity of all three oxygenators (BIOCUBE6000: R2 = 0.957, EXCELUNG PRIME: R2 = 0.946, Capiox-LX: R2 = 0.878). After 120 min of SDS solution circulation using the BIOCUBE6000, both the gas inlet pressure and the volume of fluid leaking from the membrane into the gas flow path increased in proportion to the SDS solution concentration: RO water (0.56 ± 0.11 mmHg and 16.67 mL ± 0.94 mL), 0.01% SDS (0.98 ± 0.11 mmHg and 23.3 ± 0.47 mL,) 0.1% SDS (1.64 ± 0.21 mmHg and 29.0 ± 1.63 mL), and 1%SDS (14.3 ± 0.27 mmHg and 36.7 ± 0.47 mL) (n = 3). Conclusion: This study confirmed that monitoring the gas inlet pressure changes of an oxygenator during ECMO is clinically useful.

Download Full-text

Optimization of Higher Alkanes Dehydrogenation Process under Conditions of Decreased Hydrogen Containing Gas Flow with Using Mathematical Modeling

Procedia Engineering ◽

10.1016/j.proeng.2015.07.282 ◽

2015 ◽

Vol 113 ◽

pp. 26-31

Author(s):

E.D. Ivanchina ◽

E.N. Ivashkina ◽

P.A. Glik ◽

V.V. Platonov ◽

I.M. Dolganov

Keyword(s):

Mathematical Modeling ◽

Gas Flow

Download Full-text

Mathematical Modeling of Ultrasonic Gas Flow Meter Based on Experimental Data in Three Steps

IEEE Transactions on Instrumentation and Measurement ◽

10.1109/tim.2016.2559806 ◽

2016 ◽

Vol 65 (8) ◽

pp. 1726-1738 ◽

Cited By ~ 11

Author(s):

Wen-Jiao Zhu ◽

Ke-Jun Xu ◽

Min Fang ◽

Wei Wang ◽

Zi-Wen Shen

Keyword(s):

Mathematical Modeling ◽

Experimental Data ◽

Gas Flow ◽

Flow Meter

Download Full-text

Design of a rotor for aluminum degassing assisted by physical and mathematical modeling

MRS Advances ◽

10.1557/adv.2017.590 ◽

2017 ◽

Vol 2 (61) ◽

pp. 3759-3764

Author(s):

M. Ramírez-Argáez ◽

D. Abreú López ◽

C. González Rivera

Keyword(s):

Mathematical Modeling ◽

Physical Model ◽

First Principles ◽

Gas Flow ◽

Momentum Conservation ◽

Operating Conditions ◽

Ansys Fluent ◽

Improved Design ◽

Water Saturated

ABSTRACTRecent studies on aluminum degassing [1, 2] show that although the impeller speed and the gas flow rate are important process variables in terms of the productivity and operational costs, the impeller design is also a key design parameter influencing the productivity and the quality of the aluminum in foundry shops. In this work, an improved design of an impeller is tested through a water physical model and mathematical modeling and its performance is compared against commercial designs of impellers. A full-scale water physical model of a batch aluminum degassing unit was used to test the impellers by using the same operating conditions (580 rpm and 40 liters per minute) and by performing deoxidation from water by purging nitrogen into the water saturated with oxygen (similar to the dehydrogenation). A mathematical model based on first principles of mass and momentum conservation equations was developed and solved numerically in the commercial CFD code ANSYS Fluent to describe the hydrodynamics of the system with the objective of explaining the deoxidation kinetics observed in the experiments. It has been found that the new impeller design shows a better performance than the commercial designs in terms of degassing kinetics for the conditions used in this study, which is explained since the new design promotes a flow dynamics that increases the pumping effect, creating a bigger pressure drop and fluid flow patterns which help to drag and distribute more evenly the bubbles in the entire ladle than the commercial designs.

Download Full-text