Numerical Investigation of the Dropwise Condensation Process in Top of the Line Corrosion

2019 ◽  
Author(s):  
Ibrahim E. Mohamed ◽  
Harvey M. Thompson ◽  
Richard Barker
Keyword(s):  
Condensation Process ◽  
Gas Temperature ◽  
Condensation Rate ◽  
Common Assumption ◽  
Iron Solubility ◽  
Water Condensation ◽  
Wet Gas ◽  
Condensed Water ◽  
Inlet Conditions ◽  
Good Agreement

Abstract Many approaches have been used for modelling Top of Line Corrosion (TLC) however there are a large discrepancies between their results. One common assumption is that TLC is limited by the amount of iron that can be transported with the condensed water. This means that the TLC rate is proportional to the water condensation rate and the iron solubility in the condensed phase. Therefore, a theoretical investigation is performed into the effects of gas inlet conditions on the water condensation rate in wet gas pipeline using Fluent. Comparisons were drawn with the semi-analytical model of Zhang et al. and CFD results showing good agreement between the two. The numerical results obtained reveal quantitatively how an increased inlet gas pressure leads to reductions in the condensation rate. While increasing inlet gas temperature and velocity lead to increases in condensation rate.

Investigation of Water Condensation from Humid Air and The Feasibility Analysis of its Potable Characteristics

2021 ◽  
Author(s):  
Dinesh Kumar ◽  
Vidhu Agarwal ◽  
Akhilesh Tiwari
Keyword(s):  
Produced Water ◽  
Cost Effective ◽  
Condensation Process ◽  
Humid Air ◽  
Water Condensation ◽  
Physico Chemical ◽  
Maximum Water ◽  
Peltier Device ◽  
Condensed Water ◽  
Alternative Water

Abstract Freshwater scarcity will be one of the most challenging issues in the coming time. Atmospheric water harvesting could be a solution to such a problem in semi-arid and arid regions. This could help to fill the thirst as well as, improve irrigation. There are several methods available retrieve water vapour but research is needed for a cost-effective and efficient method with optimized parameters. This method utilizes the Peltier device for water condensation and in-depth experimental analysis has been done to investigate the optimal conditions for maximum water production from atmospheric moisture. The experimental setup was designed in such a way that during the condensation process, the online monitoring of water condensate was recorded for more than 10-12 hours each day using a digital electronic weighing balance with an accuracy of 0.01 gram. The produced water was tested for the physico-chemical parameters of condensed water, and the results were discussed with a comparison to the standard results. The rate of produced condensed water from humid air was achieved as 19 L/m2-day. This study will help us to develop applications in the field of alternative water resources near the coastal areas for potability.

Analysis of Water Transport in the Vicinity of Micro-Porous Layer in PEFC With Freezing Method

2013 ◽  
Author(s):  
Yusuke Aoyama ◽  
Kengo Suzuki ◽  
Yutaka Tabe ◽  
Takemi Chikahisa
Keyword(s):  
Catalyst Layer ◽  
Cathode Side ◽  
Cross Sectional ◽  
Porous Layers ◽  
Freezing Method ◽  
Water Condensation ◽  
Flow Channels ◽  
Condensed Water ◽  
Electronic Microscope

This paper examines the role of micro porous layers (MPLs) in Polymer Electrode Fuel Cells (PEFCs) by observing the cross-sectional distribution of condensed water inside a cathode side MPL In addition, the forms of water condensation in the vicinity of a MPL are also compared between two places, under flow channels and under lands, by observing both inside the MPL and an interface between the MPL and a catalyst layer (CL). The freezing method and a cryo-scanning electronic microscope (cryo-SEM) are used for the observation. The result under the non-flooded condition shows that condensed water does not accumulate inside the MPL. This result indicates that the water produced by PEFC power generation passes through the MPL as vapor state under non-flooded conditions.

scholarly journals Estimating the Spatial Distribution of Precipitation in Iceland Using a Linear Model of Orographic Precipitation

2007 ◽  
Vol 8 (6) ◽  
pp. 1285-1306 ◽  
Author(s):  
Philippe Crochet ◽  
Tómas Jóhannesson ◽  
Trausti Jónsson ◽  
Oddur Sigurðsson ◽  
Helgi Björnsson ◽  
...  
Keyword(s):  
Linear Model ◽  
Reanalysis Data ◽  
Orographic Precipitation ◽  
Mountainous Terrain ◽  
Physical Processes ◽  
Weather Forecasts ◽  
Simulated Precipitation ◽  
Medium Range ◽  
Condensed Water ◽  
Good Agreement

Abstract A linear model of orographic precipitation that includes airflow dynamics, condensed water advection, and downslope evaporation is adapted for Iceland. The model is driven using coarse-resolution 40-yr reanalysis data from the European Centre for Medium-Range Weather Forecasts (ERA-40) over the period 1958–2002. The simulated precipitation is in good agreement with precipitation observations accumulated over various time scales, both in terms of magnitude and distribution. The results suggest that the model captures the main physical processes governing orographic generation of precipitation in the mountains of Iceland. The approach presented in this paper offers a credible method to obtain a detailed estimate of the distribution of precipitation in mountainous terrain for various conditions involving orographic generation of precipitation. It appears to be of great practical value to the hydrologists, glaciologists, meteorologists, and climatologists.

scholarly journals Optimization of bioinspired triangular patterns for water condensation and transport

2019 ◽  
Vol 377 (2150) ◽  
pp. 20190127 ◽  
Author(s):  
Dong Song ◽  
Bharat Bhushan
Keyword(s):  
Relative Humidity ◽  
Pressure Gradient ◽  
Surface Temperature ◽  
Dew Point ◽  
Laplace Pressure ◽  
Theme Issue ◽  
Water Condensation ◽  
Water Collection ◽  
Condensed Water ◽  
Droplet Condensation

Water condenses on a surface in ambient environment if the surface temperature is below the dew point. For water collection, droplets should be transported to storage before the condensed water evaporates. In this study, Laplace pressure gradient inspired by conical spines of cactus plants is used to facilitate the transport of water condensed in a triangular pattern to the storage. Droplet condensation, transportation and water collection rate within the bioinspired hydrophilic triangular patterns with various lengths and included angles, surrounded by superhydrophobic regions, were explored. The effect of relative humidity was also explored. This bioinspired technique can be used to develop efficient water collection systems. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 2)’.

Wet Gas Impeller Test Facility

2010 ◽  
Author(s):  
Trond G. Gru¨ner ◽  
Lars E. Bakken
Keyword(s):  
Oil And Gas ◽  
Fluid Dynamic ◽  
Open Loop ◽  
Gas Production ◽  
Test Facility ◽  
Atmospheric Conditions ◽  
Oil And Gas Production ◽  
Wet Gas ◽  
Inlet Conditions ◽  
The Impact

The development of wet gas compressors will enable increased oil and gas production rates and enhanced profitable operation by subsea well-stream boosting. A more fundamental knowledge of the impact of liquid is essential with regard to the understanding of thermodynamic and fluid dynamic compressor behavior. An open-loop impeller test facility was designed to investigate the wet gas performance, aerodynamic stability, and operation range. The facility was made adaptable for different impeller and diffuser geometries. In this paper, the wet gas test facility and experimental work concerning the impact of wet gas on a representative full-scale industrial impeller are presented. The centrifugal compressor performance was examined at high gas volume fractions and atmospheric inlet conditions. Air and water were used as experimental fluids. Dry and wet gas performance was experimentally verified and analyzed. The results were in accordance with previous test data and indicated a stringent influence of the liquid phase. Air/water tests at atmospheric conditions were capable of reproducing the general performance trend of hydrocarbon wet gas compressor tests at high pressure.

scholarly journals Mathematical modeling of a multi-stream brazed aluminum plate fin heat exchanger

2010 ◽  
Vol 14 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Ahmed Kohil ◽  
Hassan Farag ◽  
Mona Ossman
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Ethylene Plant ◽  
Inlet Flow Rate ◽  
Cold Stream ◽  
Inlet Conditions ◽  
Good Agreement

The need for small size and lightweight heat exchangers in many applications has resulted in the development of many heat transfer surfaces. This type of heat exchanger is much more compact than can be practically realized with circular tubes. In this work a steady-state mathematical model that representing one of the plate fin heat exchangers enclosed in cold box of an ethylene plant has been developed. This model could evaluate the performance of the heat exchanger by predicting the outlet temperatures of the hot and cold streams when the inlet conditions are known. The model has been validated by comparing the results with actual operating values and the results showed good agreement with the actual data. Sensitivity analysis was applied on the model to illustrate the main parameters that have the greatest influence on the model calculated results. The sensitivity analysis showed that the hot stream outlet temperature is more sensitive to cold streams inlet temperatures and less sensitive to hot stream inlet temperature and thermal resistance (fouling), while the cold stream outlet temperature is more sensitive to cold streams inlet flow rate and less sensitive to fouling.

Efficiency Improvement and Noise Reduction Through Stator-Stator Clocking Effect of a Two-Stage Turbine

2005 ◽  
Author(s):  
Jaroslaw R. Blaszczak
Keyword(s):  
Acoustic Noise ◽  
Experimental Investigations ◽  
Two Stage ◽  
Machine Vibration ◽  
Low Pressure Turbine ◽  
Measurement Results ◽  
Stator Vane ◽  
Flow Phenomena ◽  
Inlet Conditions ◽  
Good Agreement

The objective of the presented test program was to further experimentally investigate vane-indexing effect influence on the performance, noise and vibration of two-stage low-pressure turbine. Keeping the inlet conditions strictly constant during the tests, two turbine stages were experimentally investigated. Herein, some flow measurement results and the external characteristics for different circumferential positions of the stator vanes are described. Comparisons were made with numerical simulation and they showed good agreement. Experimental data and numerical simulations of stator vane surface pressures are presented to determine how the flow phenomena were affected by indexing of the airfoils for two cases: for nominal rotational speed and for off-design turbine conditions. In addition, correlation to acoustic noise and machine vibration level is presented. They have been found to be clocking dependent. The experimental investigations have been carried out on a two-stage turbine research facility at the Institute of Turbomachinery of the Technical University of Lodz, Poland.

Wet Gas Compressor Surge Stability

2015 ◽  
Author(s):  
Veronica Ferrara ◽  
Lars E. Bakken
Keyword(s):  
Flow Regime ◽  
High Speed ◽  
Transient Flow ◽  
Focal Point ◽  
Operating Conditions ◽  
Concept Design ◽  
Wet Gas ◽  
Compressor Surge ◽  
Inlet Conditions ◽  
The Impact

The new wet gas compression technology provides a big potential for improved recovery from new and depleting gas/condensate fields. The current technology is based on centrifugal and axial compressor principles, which offers both the benefits of well-known concept design and the drawbacks of erosion, fouling, surge and instabilities. These concepts are based mainly on the design of a traditional compressor. This partly reflects performance requirements for handling pure gas and partly the lack of a fundamental understanding of wet gas behaviour through an impeller stage. Process and operating conditions may vary considerably during start-up at gas only or completely filled with addition of liquid with an inlet and/or discharge transient flow regime. An advanced wet gas test rig has been designed to identify the fundamental mechanisms related to wet gas compressor surge and instability behaviour. The open-loop wet gas rig includes a single overhung impeller, sections of visualisation for the wet gas impeller inlet, discharge and diffuser. The paper reviews and exposes the instabilities and surge flow behaviour at the impeller eye. Main focuses are the shift in inlet flow regime, the impact on overall compressor stage performance and the ability to handle wet transient inlet conditions. Any flow separation and/or slip across the inlet and impeller eye section will alter the established dry gas design guide lines for compressors. Visualisation of the impeller inlet during surge progression is the focal point of the present study. The investigation is supplemented by fast Fourier transform (FFT) analyses and high-speed measurements.

scholarly journals Extension of Weighted Sum of Gray Gas Data to Mathematical Simulation of Radiative Heat Transfer in a Boiler with Gas-Soot Media

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Samira Gharehkhani ◽  
Ali Nouri-Borujerdi ◽  
Salim Newaz Kazi ◽  
Hooman Yarmand
Keyword(s):  
Heat Transfer ◽  
Absorption Coefficient ◽  
Radiative Heat ◽  
Measured Data ◽  
Weighted Sum ◽  
Gas Temperature ◽  
Zone Method ◽  
Plant Site ◽  
Good Agreement ◽  
Steam Production

In this study an expression for soot absorption coefficient is introduced to extend the weighted-sum-of-gray gases data to the furnace medium containing gas-soot mixture in a utility boiler 150 MWe. Heat transfer and temperature distribution of walls and within the furnace space are predicted by zone method technique. Analyses have been done considering both cases of presence and absence of soot particles at 100% load. To validate the proposed soot absorption coefficient, the expression is coupled with the Taylor and Foster's data as well as Truelove's data for CO2-H2O mixture and the total emissivities are calculated and compared with the Truelove's parameters for 3-term and 4-term gray gases plus two soot absorption coefficients. In addition, some experiments were conducted at 100% and 75% loads to measure furnace exit gas temperature as well as the rate of steam production. The predicted results show good agreement with the measured data at the power plant site.

On longitudinal vortices in curved channel flow

1993 ◽  
Vol 251 ◽  
pp. 627-660 ◽  
Author(s):  
Alessandro Bottaro
Keyword(s):  
High Speed ◽  
Curved Channel ◽  
Longitudinal Vortices ◽  
Dean Vortices ◽  
Vortex Pairs ◽  
Spatial Approach ◽  
Temporal Model ◽  
Inlet Conditions ◽  
Curved Channel Flow ◽  
Good Agreement

The laminar flow in a curved channel is studied numerically to analyse the initial formation, development and interaction phenomena of an array of centrifugally induced longitudinal vortices arranged across the span of the channel. Simulations employing streamwise periodic boundary conditions (temporal model) as well as inlet-outlet conditions (spatial model) are carried out. In the temporal approach the interactions (pairing of vortices and growth of new vortex pairs) of fully developed vortex pairs are time-dependent, whereas in the spatial approach these events are inherently steady and concern vortices not in their fully developed state. The initial spatial development of the vortices is in excellent agreement with results of a linear stability analysis up to fairly large disturbance amplitudes. In the nonlinear regime a good agreement with experimental results has also been found. The receptivity of the flow is very important in a convectively unstable situation such as the present one and different behaviour is found at fixed Reynolds number (equal to 2.43 times the critical value for the onset of Dean vortices): the flow can be either steady or undergo a continuous sequence of merging and splitting events, depending on the inlet conditions. In the latter situation decorrelated patterns of low- and high-speed streaks are produced in streamwise-spanwise planes and they bear several similarities to near-wall coherent structures of turbulent boundary layers.

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