UV Radiation Distribution in A Flat-Plate Photocatalytic Reactor with Suspended Particles of Titanium Dioxide. Mathematical Model and Experimental Verification

1998 ◽  
Vol 3 (3) ◽  
Author(s):  
Rodolfo J. Brandi ◽  
Orlando M. Alfano ◽  
Alberto E. Cassano
Keyword(s):  
Mathematical Model ◽  
Flat Plate ◽  
Coming Out ◽  
Radiation Flux ◽  
Radiation Energy ◽  
Photocatalytic Reactor ◽  
Radiation Fluxes ◽  
Radiation Distribution ◽  
Parabolic Reflectors ◽  
Uv Lamps

AbstractA two-dimensional - two-directional mathematical model of the radiation field inside a flat-plate, photocatalytic reactor has been developed. The slurry-type reactor is irradiated by two tubular UV lamps with the aid of two parabolic reflectors. Resorting to information about the reactor dimensions, the lamp and reflector characteristics, and the catalyst optical properties and concentration, the solution of the mathematical model provides a detailed description of the rate of absorbed radiation energy at each point inside the reactor. The radiation distribution inside the reactor was verified by computing the radiation flux coming out of the reactor at the opposite face of the radiation entrance. These radiation fluxes were compared with experimental measurements made with a UV radiometer and good agreement was obtained; the maximum observed error was 12%. When the catalyst concentration was increased, a significant decrease of the radiation flux leaving the reactor was also observed.

scholarly journals Mathematical Model to Optimize Production of Loading-Unloading Operations on the Vessel

2020 ◽  
pp. 29-30
Author(s):  
Ibraim Didmanidze ◽  
Givi Tsitskishvili
Keyword(s):  
Mathematical Model ◽  
Decision Making ◽  
Coming Out ◽  
Scientific Work ◽  
Equal Strength ◽  
Optimal Classification ◽  
A Priority ◽  
The Given

In scientific work it is shown, that our goal is to choose the desired option from variety of alternatives (in our case different options of loading-unloading operations on the vessel) or to take decision which is the best (optimal). Classification in this case is the grounds, as taking the choice is based on choosing certain class, which can be assigned to an alternative. Stratification and rating gives us wide option to make reasonable selection, or to take a kind of decision which will be optimal for the certain moment and occasion. These methods can be used with equal strength at all stages of the processes taking place in the area of current decision making management. This refers to the object of our study of course – solution of selecting optimal option to optimize loading-unloading operation on the vessel. It goes without saying that variety of alternatives doesn’t have any structure, thus abundance of each element was never structured randomly retrieved or no consideration has been proposed, and they are not a priority and in any order. Coming out of this it’s impossible to mention which alternative is better and which is less desirable. In order to solve the task of selecting a set of alternatives successfully, it is necessary, to make structure of the given abundance of alternatives in any form.

The DRESOR Method for a Collimated Irradiation on an Isotropically Scattering Layer

2006 ◽  
Vol 129 (5) ◽  
pp. 634-645 ◽  
Author(s):  
Qiang Cheng ◽  
Huai-Chun Zhou
Keyword(s):  
Heat Transfer ◽  
Monte Carlo ◽  
Radiative Heat ◽  
Radiation Flux ◽  
Solid Angle ◽  
Heat Transfer Process ◽  
Arbitrary Direction ◽  
Scattering Layer ◽  
Radiation Fluxes ◽  
Angle Space

Forward and backward Monte Carlo methods may become inefficient when the radiant source is collimated and radiation onto a small, arbitrary spot and onto a small, arbitrary direction cone is desired. In this paper, the DRESOR method was formulated to study the radiative heat transfer process in an isotropically scattering layer exposed to collimated radiation. As the whole spherical solid angle space was uniformly divided into 13,316 discrete solid angles, the intensity at some point in up to such discrete directions was given. The radiation fluxes incident on a detector inside the layer for varying acceptance angles by a step of 2deg were also measured, which agreed well with those in literature. The radiation flux across the top and the bottom boundaries were also provided.

Mathematical Model of Forecasting the Formation of Sinkhole Using Salustowicz’s Theory / Model Matematyczny Prognozowania Zapadlisk Przy Wykorzystaniu Teorii Sklepienia Ciśnień Sałustowicza

2015 ◽  
Vol 60 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Piotr Strzałkowski
Keyword(s):  
Mathematical Model ◽  
Stress State ◽  
Flat Plate ◽  
Theory Model ◽  
Security Issues ◽  
Urbanized Areas ◽  
Working Out ◽  
Made In

Abstract In area affected by old, shallow extraction in some cases sinkholes are formed, causing security issues in urbanized areas. Problem of working out deterministic forecast of this threat seems to be important and up-to-date. Mathematical model presented in this work let us predict the possibility of sinkhole formation. That prediction is essential for analyzing possibility of investments in such areas. Basing on presented work, it is also possible to determine dimensions of sinkhole. Considerations are based on known from literature Sałustowicz’s theory, which is utilises Huber’s solution of equation describing the stress state around elliptic void made in flat plate

Relation between Collector Efficiency Factor and the Centre to Centre Distance of Absorber Tubes of Solar Flat-Plate Collector

2014 ◽  
Vol 592-594 ◽  
pp. 2404-2408 ◽  
Author(s):  
Sunita Meena ◽  
Chandan Swaroop Meena ◽  
V.K. Bajpai
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Flat Plate ◽  
Special Kind ◽  
Radiation Energy ◽  
Efficiency Factor ◽  
Energy Gain ◽  
Absorber Plate ◽  
Collector Efficiency ◽  
Flat Plate Collector

Solar energy collectors are a special kind of heat exchangers that transform solar radiation energy to internal energy of the transport medium. The major component of any solar system is the solar collector. This is a device which absorbs the incoming solar radiation, converts it into heat, and transfers this heat to a fluid (usually air, water, or oil) flowing through the collector. The measurement of the flat plate collector performance is the collector efficiency. The collector efficiency is the ratio of the useful energy gain to the incident solar energy over a particular period of time. The useful energy gain is strongly depends on the collector efficiency factor and this factor directly influenced by few parameters i.e. the centre to centre distance of absorber tubes W , thickness of absorber plate δ and heat loss coefficient UL. This paper has been focused on the relation between W with collector efficiency factor of serpentine tube solar flat-plate collector. This study shows that if we increase the W then Fˈ decreases.

Modeling of a Flat Plate, Slurry Reactor for the Photocatalytic Degradation of 4-Chlorophenol

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
María Lucila Satuf ◽  
Rodolfo J Brandi ◽  
Alberto E Cassano ◽  
Orlando M Alfano
Keyword(s):  
Photocatalytic Degradation ◽  
Flat Plate ◽  
Radiation Effects ◽  
Heterogeneous Photocatalysis ◽  
Slurry Reactor ◽  
Catalyst Loading ◽  
Wide Range ◽  
Laboratory Scale Reactor ◽  
Uv Lamps ◽  
Intrinsic Kinetic

Heterogeneous photocatalysis employing titanium dioxide has emerged as an efficient method to remove a wide range of toxic compounds from polluted waters. In particular, chlorophenols constitute an important group of aquatic contaminants that have been successfully degraded by photocatalysis. In this work, the modeling of a slurry reactor for the photocatalytic degradation of 4-chlorophenol (4-CP) is presented. The experimental reactor is a thin rectangular parallelepiped limited by two parallel windows made of borosilicate glass. It is illuminated from one side by two tubular UV lamps (UV Philips TLK40/09N) located at the focal axis of cylindrical reflectors of a parabolic cross-section. The flat plate reactor is placed inside the loop of an isothermal, batch recycling system. The model describes the degradation of 4-CP as well as the formation and disappearance of the main intermediate products: 4-chlorocatechol (4-CC) and hydroquinone (HQ). Intrinsic kinetic expressions, previously obtained in a laboratory scale reactor, were employed to solve the mass balance for each species. To take account of the radiation effects on the reaction rate, the radiative transfer equation was solved in the flat plate reactor. The radiation model involves two spatial variables and two angular variables in the direction of radiation propagation.To validate the model, experimental runs were conducted by varying the catalyst loading (0.05, 0.1, 0.5, 1.0 x 10-3 g/cm3) and the 4-CP initial concentration (0.7 and 1.4 x 10-7 mol/cm3). Good agreement was found between simulation results and experimental data. Based on the experimental and predicted concentrations of 4-CP and 4-CC, the root mean square error (RMSE) of the model was 9.9 %.

Numerical Simulation of Flow in a Photocatalytic Reactor Containing Baffles

2011 ◽  
Author(s):  
Saber Ahmed ◽  
M. G. Rasul ◽  
R. J. Brown ◽  
J. Esteban Duran
Keyword(s):  
Fluid Dynamics ◽  
Wastewater Treatment ◽  
Flat Plate ◽  
Vortex Formation ◽  
Underlying Mechanism ◽  
Valuable Insight ◽  
Photocatalytic Reactor ◽  
Flow Features ◽  
Computational Fluid Dynamics Cfd ◽  
Stream Lines

In this study a new immobilized flat plate photocatalytic reactor for wastewater treatment has been investigated using computational fluid dynamics (CFD). The reactor consists of a reactor inlet, a reactive section where the catalyst is coated, and outlet parts. For simulation, the reactive section of the reactor was modelled with an array of baffles. In order to optimize the fluid mixing and reactor design, this study attempts to investigate the influence of baffles with differing heights on the flow field of the flat plate reactor. The results obtained from the simulation of a baffled flat plate reactor hydrodynamics for differing baffle heights for certain positions are presented. Under the conditions simulated, the qualitative flow features, such as the distribution of local stream lines, velocity contours, and high shear region, boundary layers separation, vortex formation, and the underlying mechanism are examined. At low and high Re numbers, the influence of baffle heights on the distribution of species mass fraction of a model pollutant are also highlighted. The simulation of qualitative and quantitative properties of fluid dynamics in a baffled reactor provides valuable insight to fully understand the effect of baffles and their role on the flow pattern, behaviour, and features of wastewater treatment using a photocatalytic reactor.

Solar Radiation Distribution Method for a Photovoltaic Greenhouse based on the Maximization of Annual Economic Benefits

2021 ◽  
Author(s):  
Yi Wang ◽  
Tiejun Zhou ◽  
Weiji Zhou
Keyword(s):  
Mathematical Model ◽  
Power Generation ◽  
Solar Radiation ◽  
Agricultural Production ◽  
Crop Production ◽  
Economic Benefits ◽  
Distribution Method ◽  
Greenhouse Crops ◽  
Photovoltaic Power ◽  
Radiation Distribution

Abstract A solar radiation distribution method is proposed based on the maximization of economic benefits for photovoltaic power generation and agricultural production in a photovoltaic greenhouse to solve the problem of low overall economic benefits because of an unreasonable solar radiation distribution between photovoltaic power generation and agricultural production in the photovoltaic greenhouse. First, a mathematical model of the solar radiation yield of photovoltaic greenhouse crops is proposed based on a rectangular hyperbolic modified light response model of crops to represent the relationship between solar radiation energy and crop production. Second, a mathematical model of the average annual revenue of a photovoltaic greenhouse is established to determine the maximum annual economic benefit of the photovoltaic greenhouse, and the model is constrained by the requirements of the light intensity of photovoltaic power generation and environmental conditions for the growth of greenhouse crops. Finally, the correctness of the model is verified by actual operation data of a photovoltaic greenhouse in Xinjiang, and the optimal solar radiation distribution proportion is calculated. This study provides theoretical support for the design of photovoltaic greenhouses.

CFD + DoE optimization of a flat plate photocatalytic reactor applied to NOx abatement

2020 ◽  
Vol 154 ◽  
pp. 107998 ◽  
Author(s):  
Jéssica O.B. Lira ◽  
Humberto G. Riella ◽  
Natan Padoin ◽  
Cíntia Soares
Keyword(s):  
Flat Plate ◽  
Photocatalytic Reactor ◽  
Nox Abatement
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