ALT Model Development and Implementation for High Pressure Rotary Valves

2019 ◽  
Author(s):  
Kurt Banker
Keyword(s):  
High Pressure ◽  
Model Development ◽  
Alt Model ◽  
Rotary Valves

scholarly journals Machine Learning for Turbulence Model Development Using a High-Fidelity HPT Cascade Simulation

2017 ◽  
Author(s):  
Jack Weatheritt ◽  
Richard Pichler ◽  
Richard D. Sandberg ◽  
Gregory Laskowski ◽  
Vittorio Michelassi
Keyword(s):  
High Pressure ◽  
Evolutionary Algorithm ◽  
Turbine Blade ◽  
A Priori ◽  
Model Development ◽  
Boussinesq Approximation ◽  
High Pressure Turbine ◽  
Stress Strain ◽  
Non Linear ◽  
Anisotropy Tensor

The validity of the Boussinesq approximation in the wake behind a high-pressure turbine blade is explored. We probe the mathematical assumptions of such a relationship by employing a least-squares technique. Next, we use an evolutionary algorithm to modify the anisotropy tensor a priori using highly resolved LES data. In the latter case we build a non-linear stress-strain relationship. Results show that the standard eddy-viscosity assumption underpredicts turbulent diffusion and is theoretically invalid. By increasing the coefficient of the linear term, the farwake prediction shows minor improvement. By using additional non-linear terms in the stress-strain coupling relationship, created by the evolutionary algorithm, the near-wake can also be improved upon. Terms created by the algorithm are scrutinized and the discussion is closed by suggesting a tentative non-linear expression for the Reynolds stress, suitable for the wake behind a high-pressure turbine blade.

Strain Demand Estimation for Pipelines in Challenging Arctic and Seismically Active Regions

2010 ◽  
Author(s):  
Haydar Arslan ◽  
Jed Hamilton ◽  
Suvrat Lele ◽  
Karel Minnaar ◽  
Bob Albrecht ◽  
...  
Keyword(s):  
High Pressure ◽  
Model Development ◽  
Active Regions ◽  
Demand Estimation ◽  
Plastic Strains ◽  
Offshore Pipelines ◽  
Demand Prediction ◽  
Proper Design ◽  
Conducting Research ◽  
High Temperature High Pressure

The need to use strain-based design is growing due to potential pipeline projects in environments that include permafrost, offshore ice hazards, active seismic areas and high temperature/high pressure operations. Proper design and construction of such pipelines poses numerous special challenges and requires consideration of some important processes that govern the behavior of soils. ExxonMobil has been conducting research to improve understanding of geotechnical mechanisms that result in large plastic strains in the pipelines, and to develop pipeline strain demand prediction methodologies in harsh arctic and seismically active regions. This paper discusses key challenges in strain demand estimates for Arctic onshore and offshore pipelines and is aimed at promoting industry discussion of strain demand prediction methodologies. The paper highlights ExxonMobil’s efforts in developing predictive technologies for strain demand estimation that forms the basis for the design, testing, and model development in strain-based pipeline applications.

Dynamic Simulation of Coal-Fired Power Plant Integrated With Trough Solar Collector Operating in Parallel With High Pressure Heaters

2020 ◽  
Author(s):  
Hui Yan ◽  
Xin Li ◽  
Ming Liu ◽  
Daotong Chong ◽  
Junjie Yan
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Solar Energy ◽  
Response Time ◽  
Dynamic Performance ◽  
Model Development ◽  
Load Ratio ◽  
Power Variation ◽  
Power Load ◽  
Mass Flowrate

Abstract Solar-aided coal-fired power plant (SACFPP) is a cost-effective approach to overcome solar energy intermittency. SACFPPs frequently operate in dynamic processes due to power load and solar energy fluctuations. This study investigated the dynamic characteristics of SACFPPs; such characteristics are important for flexibility evaluation and control system design. The SACFPP used in this study was based on a 660 MW coal-fired power plant, and a trough collector system (TCS) operates in parallel with high pressure (HP) heaters. After model development and validation, the dynamic performance of the SACFPP was analyzed under four load ratios of power plant, with disturbances of two parameters: direct normal irradiance (DNI) and mass flowrate ratio to TCS. The performance was also compared with three parallel TCS connection modes. Results showed that the magnitude and response time for power variation under DNI disturbance increased with load ratio. With 500 W/m2 DNI step increments, power increased by approximately 18.4, 21.2, 24.7, and 29.8 MW in 2200, 2330, 2550 and 2620 s at 70%, 80%, 90%, and 100% load ratios, respectively, when all the HP heaters were replaced. The serial number and the number of HP heaters replaced also increased the power variation and response time. Under mass flowrate ratio to TCS increase disturbance, the power rapidly changed to its maximum and then slowly decreased, but the variation value depended on the load ratio.

scholarly journals Thermal model development and validation for rapid filling of high pressure hydrogen tanks

2015 ◽  
Vol 40 (31) ◽  
pp. 9803-9814 ◽  
Author(s):  
Terry Johnson ◽  
Radoslav Bozinoski ◽  
Jianjun Ye ◽  
George Sartor ◽  
Jinyang Zheng ◽  
...  
Keyword(s):  
High Pressure ◽  
Thermal Model ◽  
Model Development ◽  
Development And Validation ◽  
Pressure Hydrogen

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

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