Prediction Of Evaporation Rate Research Articles

Analysis and prediction of evaporation rates using random forest models: a case study of Almaty city

In this study, Climate Research Unit (CRU) data crossing from 1901 to 2022 was utilized to analyze and predict evaporation rates in Almaty, Kazakhstan. The data was prepared utilizing Python, leveraging the Random Forest (RF) machine learning Techniques for its capability to handle complex and non-linear information. The essential measurements for assessing the model's execution were Cruel Supreme Blunder (MAE), Root Cruel Square Mistake (RMSE), and Cruel Squared Mistake (MSE). The Random Forest model was utilized in prediction and data examination. This model is recognized by its capacity to process non-linear and complex data by making a set of choice trees and joining their comes about to get exact and steady predictions. The model is based on arbitrary testing with bootstrap testing, which makes a difference decrease change and increment the precision of the demonstrate.

Spatially dependent salinity effect in actively vacuumed spray flash desalination

Spray flash desalination is one of the most promised distillation methods, which is realized by spraying the superheated droplets into a depressurized chamber to generate flash evaporation. This intensive evaporation leads to a strongly temperature-salinity coupled polarization near the surface region within droplets, which in turn reduces the evaporation rate. In a spray flash desalination chamber with active vacuuming of vapor extraction, such internal polarizations also weaken the thermal non-equilibrium between the extracted hot vapor and the discharged cooler feed residue during the process. This paper aims to establish an integrated modeling-experiment-CFD methodology for quantifying the spatially dependent salinity effect within droplets to the overall processing characteristics in an actively vacuumed spray flash desalination, such as the evaporation rate and efficiency, the coupled internal heat conduction and salt diffusion within droplets, the thermal non-equilibrium between vapor and spray, as well as the non-uniformed vapor flow from vacuum extraction. Specifically: the heat conduction and salt diffusion coupled droplet flash model is proposed; a further simplified point-based droplet flash model is established for CFD simulations; an experimental system of spray flash desalination with active vacuuming is developed for model validations. The evaporation rate and the thermal non-equilibrium are found to be positively related to the initial superheat levels of the spray but negatively impacted by the initial salinity. Modeling predictions indicate that ignoring the spatial dependence of salinity can over-estimate the flash rate by up to 30% in high salinity cases of salty-water distillation. The thermal non-equilibrium between vapor and feed can be effectively generated under active vacuum, even with a low initial superheat level and high salinity. Increasing feed salinity from 0% to 10% in different cases will narrow the temperature gap between outlet vapor and feed residue by about 10% on average. For typical industrial flash desalination (with salinity up to 10%), with or without considering the spatial dependence of salinity will cause relatively minor differences (less than 5%) on the prediction of evaporation rate.

Droplet Evaporation Dynamics on Hydrophobic Network Surfaces.

Surface modification, such as hydrophobic network modification, is very promising technology to control droplet dynamics, heat transfer, and evaporation. However, fundamental mechanisms of how these chemically patterned surfaces affect the droplet evaporation dynamics and predictions of evaporation rates are still lacking. In the present work, we systematically investigated the full process of droplet evaporation dynamics on hydrophobic network surfaces and distinguished four different stages: constant contact line (CCL) stage, constant contact angle (CCA) stage, pattern-pinning (PP) stage, and moving contact line (MCL) stage. We further developed a general model considering the pinning and depinning forces to accurately predict the evaporation transition from PP to MCL stages (i.e., critical receding contact angle, θcr). As for the influence of the chemically patterned surface on the evaporation rate, a corrected contact line length was considered and combined with the well-known Rowan and Erbil's models. Finally, a general model was thus proposed and showed successful predictions for the evaporation durations of each stage.

THE EFFECT OF STEFAN FLOW ON THE MODELS OF DROPLET EVAPORATION

Droplet evaporation has been widely studied in the literature due to its key role in various applications in science and industry. The problem of droplet evaporation involves various mechanisms in both liquid and vapor phases together with the interface separating them. Modeling of this multiphase problem is not straightforward thereof studied by many researchers but in every time a few different contributing mechanisms could be highlighted. One of the pieces of this puzzle is undoubtedly the Stefan flow, which is always present during the evaporation of a liquid to an insoluble surrounding gas, yet the number of studies exploring its individual contribution to the evaporation remain very restricted. In the current study, the effect of Stefan flow is assessed by employing a recent state-of-the-art model that accounts for all pertinent physics of droplet evaporation. Results reveal that Stefan flow can be responsible for 17% of total evaporation when the droplet is placed on a high temperature substrate. Moreover, it is shown that lower performance of diffusion based models (in gas phase) can be greatly enhanced by incorporating the effect of Stefan flow into the interfacial mass flux equation. In addition, performances of existing purely diffusion and diffusion and Stefan flow based correlations in the prediction of evaporation rates are elucidated. Last but not least, under varying humidity of the surrounding gas, contribution of individual transport mechanisms in gas phase to the total evaporation rate is found to be unaffected. Based on this result, it is hypothesized that contributions of Stefan flow and natural convection have a linear dependence on the contribution of sole diffusion. The current study clearly demonstrated that Stefan flow considerably enhances the evaporation rate of droplets, especially in the case of high substrate heating. Therefore, future studies on the topic should account for the Stefan flow during the modeling of droplet evaporation.

Calculation of Evaporation From Fukushima Nuclear Power Plant Spent Fuel Pools

Prediction of evaporation rates from spent fuel pools of nuclear power plants in normal and postaccident conditions is of great importance for the design of safety systems. A severe accident in 2011 Fukushima nuclear power plant caused failure of cooling systems of its spent fuel pools. The postaccident evaporation from the spent fuel pools of Fukushima units 2 and 4 is compared to a model based on analogy between heat and mass transfer which has been validated with a wide range of data from many water pools including a spent fuel pool. Calculations are done with two published estimates of fuel decay heat, one 25% lower than the other. The model predictions are close to the evaporation using the lower estimate of decay heat. Other relevant test data are also analyzed and found in good agreement with the model.

Experimental Study of the Rate of Evaporation from Porous Media of Different Matrices

Evaporation and boiling from porous media has drawn a broad attention in many applications ranging from industrial, environmental to engineering and technologies. However, prediction of evaporation rates from porous media remains a challenge due to complex interactions between ambient conditions and the porous media properties such as complex geometry, material of the matrices composing porous medium, many length scales, surface phenomena, and effective transport coefficients. In this study, the evaporation rates of distilled water from porous media of different matrices were studied experimentally. Porous media were made up from spherical brass balls of different diameters of 2 mm, 3 mm, 4 mm and 5 mm. The temperature profiles across porous media, air temperature, humidity, and amount of water evaporated were measured in experiments. The effects of the porosity, the thickness of a porous layer, and particle size on the evaporation from porous media were investigated. Different materials of the porous matrices have allowed bringing to light the influence of the material properties. The experimental data show that the rate of evaporation of distilled water with brass balls is higher than that of only distilled water without a porous medium embedded into the water layer and does not change significantly after a steady state condition is achieved.

Modeling of Mass Transfer During Hot-Smoking of Fish Fillets

This work aims at evaluating the mass reduction of traditionally hot-smoked catfish ( Arius heudelotii ) during hot-air drying unit operation. Drying kinetics of fish fillets are proposed from experimental investigations, taking into account the relative contributions of water evaporation and water and fat drips. The influence of the air temperature (50 to 80 ∘ C), air velocity (1 to 3 m/s) and relative humidity (15 to 40%) on drying rate functions is analyzed from a Doehlert experimental design. Based on the identification of characteristic drying rate curves, a drying model is defined and proves to be quite accurate regarding the prediction of evaporation rate during the falling rate period.

Simulation model for an EB-PVD coating structure using the level set method

A comprehensive modeling approach to link machine dynamics, deposition, and substrate kinematics in an electron beam physical vapor deposition (EB-PVD) is presented in this paper. The machine dynamics in EB-PVD process are captured by finite element models, resulting in the prediction of evaporation rate and vapor distribution. The deposition process is modeled using the level set method, which is one of the computational techniques for tracking topographic evolution. The proposed simulation model is implemented in Matlab and is compared with experimental results published by other researchers. Results indicate that the proposed simulation model can be used to predict microstructure features such as zigzag and helical columnar shapes. The pitch of a zigzag microstructure can be predicted within 20% at the 0.3 to 6 μm level for Yttira-stabilized Zirconia (YSZ) coating.

Average Vaporisation Rate in Turbulent Subcritical Two-Phase Flow

This work considers alternative expressions for turbulent evaporation rate used in the framework of an entirely Eulerian model based on a transport equation for the average liquid surface area. Commonly employed expressions for vaporisation rate derived from Spalding-Godsave theory fail to account for vaporisation enhancement induced by turbulence; moreover, they do not describe experimentally observed fact that the pressure affects vaporisation rate differently in a turbulent and a laminar flow. To address these shortcomings, an alternative formula for the vaporisation rate is proposed based on an assumption that the vaporisation rate is governed by a small-scale turbulence. This model is assessed for a range of pressure and temperature conditions, using experiments of Brandt et al. (1997a) performed in a premix duct with a flat-bed atomiser as the test case. Turbulence intensities and scales in the chosen test case are typical for a modern gas-turbine combustion chamber. This new expression results in prediction of evaporation rate and SMD in a good agreement with experimental results.

Transient Behavior of a Solar Pond and Prediction of Evaporation Rates

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransient Behavior of a Solar Pond and Prediction of Evaporation RatesS. PancharatnamCite this: Ind. Eng. Chem. Process Des. Dev. 1972, 11, 2, 287–292Publication Date (Print):April 1, 1972Publication History Published online1 May 2002Published inissue 1 April 1972https://doi.org/10.1021/i260042a023RIGHTS & PERMISSIONSArticle Views134Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (601 KB) Get e-Alerts