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Desenvolvimento e validação de uma rede neural para análise de fluxo crítico de calor em reatores nucleares do tipo PWRTerng, Nilton January 2015 (has links)
Orientador: Prof. Dr. Pedro Carajilescov / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, 2015. / Fluxo Crítico de Calor (FCC) consiste no principal limite termohidráulico de reatores do
tipo PWR, que representa a opção nuclear brasileira. Trata-se, ainda, de um fenômeno
de entendimento limitado. Em projetos, a estimativa de seu valor é realizada apenas
por correlações empíricas, resultando valores aproximados, com elevadas incertezas.
O presente projeto consiste no desenvolvimento de um método computacional para o
cálculo do FCC, através de conceitos de Redes Neurais Artificiais, programado na
linguagem Fortran, utilizando para treinamento e teste os dados das chamadas "Look
up Tables" (LUT). Considerou-se a faixa de variação dos dados das tabelas, com a
pressão variando de 1 e 21 MPa, fluxo de massa, na faixa de 50 a 8000 kg m-2 s-1 e
título do escoamento entre - 0,5 a 0,9. Comparando os resultados da RN com a LUT, a
média da razão dos valores resultou em 0,993, com o erro médio quadrático de 13,3%.
Com a rede neural foi realizado o estudo paramétrico do FCC, para observar a
influência dos parâmetros operacionais tais como pressão, fluxo de massa e título
termodinâmico. Observa-se o aumento do FCC com o aumento do fluxo de massa e a
atenuação do FCC com o aumento da pressão e título, como esperado. Porém
algumas tendências imprevistas ocorreram, as quais podem ser atribuídas à incerteza
dos dados, ou por fatos desconhecidos do fenômeno.
A aplicação da rede neural em geometrias de feixe de varetas com arranjo quadrado
apresentou bons resultados pelo método de balanço de energia (HBM) e a correção
de PEI com erro médio quadrático de até 20,08%. Pelo método da substituição direta
(DSM), foram elaborados diversos métodos de correção para adaptar os valores da
rede neural à geometria de feixe de varetas. Os resultados não foram satisfatórios,
pois apresentaram erro médio quadrático elevado, sendo o menor erro médio
quadrático alcançado de 19,92%, utilizando uma rede neural com o espectro de
parâmetros de entradas restritos e fator de correção multivariável. A correlação de
EPRI com a correção de PEI apresentou resultado de erro médio quadrático de
18,73%, sendo menor que todos os métodos desenvolvidos nesse projeto.
Portanto, o método de rede neural, desenvolvido nesse trabalho, não se revelou
satisfatório para aplicação em feixe de varetas. / The critical heat flux (CHF) is one of the principal thermal hydraulic limits of PWR type
nuclear reactors. To date, the CHF phenomenon is not well understood. So, for design
purpose, the CHF is usually estimated by empirical correlation, resulting in approximate
values, with high uncertainties. As an alternative to traditional methods, the present
work consists in the development of an artificial neural network (ANN) to estimate the
CHF, based on Look Up Table CHF data, published by Groeneveld (2006). Three
parameters were considered in the development of the ANN: the pressure in the range
of 1 to 21 MPa, the mass flux in the range of 50 to 8000 kg m-2 s-1 and the
thermodynamic quality in the range of - 0,5 to 0,9. Comparing the ANN predictions with
the data of the Look Up Table, it was observed an average of the ratio of 0.993 and a
root mean square error (rms) of 13.3%.
With the developed ANN, a parametric study of CHF was performed to observe the
influence of each parameter in the FCC. It was possible to note that the CHF
decreases with the increase of pressure and thermodynamic quality, while CHF
increases with the mass flow rate, as expected. However, some erratic trends were
also observed which can be attributed to either unknown aspect of the FCC
phenomenon or uncertainties in the data.
The ANN application in square array of rods bundle demonstrated nice result for the
heat balance method (HBM) with the PEI correction resulting in rms of 20,08%. A few
methods of correction were developed for the direct substitution method (DSM) to
adapt the ANN in rod bundle geometry. The results wasn¿t satisfactory, because the
best rms reached was 19.92%, using the ANN with restricted input range and
multivariable correction factor. EPRI correlation with PEI correction results in rms of
18.73%, being better than all of developed methods in this project.
Therefore, the ANN method, developed in this work, does not seem to be satisfactory
for the application in rod bundle.
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Medição da velocidade de queima laminar de biogás e gás de síntese através do método do fluxo de calor e comparação com mecanismos cinéticosNonaka, Hugo Ohno Barbosa January 2015 (has links)
A velocidade de queima laminar adiabática é um importante parâmetro da combustão que dita o comportamento de chamas pré-misturadas. Dos métodos disponíveis para a medição desse parâmetro, o método do fluxo de calor destaca-se pela simplicidade e precisão. No presente trabalho, esse método é utilizado para medir a velocidade de queima de biogás (modelado como CH4 com diferentes níveis de diluição com CO2) e de gás de síntese (modelado como uma mistura de CH4, H2, CO, CO2 e N2) em ar a 298 K e 1 atm. Tais gases são de crescente interesse para a sociedade em função de aspectos ambientais, porém, suas velocidades de queima não foram amplamente estudadas ainda. Os resultados obtidos são comparados com as previsões de cinco mecanismos cinéticos (GRI-Mech 3.0, Davis et al., Konnov, San Diego e USC Mech II) a fim de avaliar a sua capacidade preditiva. Os resultados experimentais e numéricos das velocidades de queima de biogás e ar apresentam uma boa concordância e as incertezas encontradas foram condizentes com as relatadas na literatura. Os resultados experimentais desse gás foram parametrizados em uma correlação empírica de fácil utilização em modelos numéricos. As medições da velocidade de queima de gás de síntese e ar, por outro lado, apresentaram valores inferiores às previsões numéricas de todos os mecanismos estudados. Os dados experimentais da literatura, para a mesma mistura, diferem tanto em valores quanto em comportamento dos resultados do presente trabalho. Tal comportamento está provavelmente relacionado a alguma contaminação no CO utilizado, já que quando esse gás está presente observa-se uma chemi-luminescência não relatada na literatura. / The adiabatic laminar burning velocity is an important combustion parameter that dictates premixed flames characteristics. Among the measuring methods available in literature, the heat flux method stands out for its simplicity and accuracy. In the present work, this method is used to measure the adiabatic laminar burning velocity of biogas (modeled as CH4 with different dilution levels with CO2) and syngas (modeled as a CH4, H2, CO, CO2 and N2 mixture) in air at 298 K and 1 atm. Such gases are of growing society interest due to environmental aspects, however, their adiabatic laminar burning velocity have not been widely studied yet. The experimental results are compared to predictions of five kinetic mechanisms (GRI-Mech 3.0, Davis et al., Konnov, San Diego e USC Mech II) to evaluate their predictive capacity. Experimental and numerical results of biogas/air mixtures adiabatic laminar burning velocity show good agreement and the found uncertainties are in agreement with literature. Experimental results of this gas were fitted in an empiric correlation of simple numerical application. Experimental results of the laminar burning velocity of syngas/air, on the other hand, show lower values than the numerical predictions of all studied kinetic mechanisms. Literature available data for the same mixture differ both in values and behavior of the present work results. Such behavior is probably related to some contamination on the CO used since a chemi-luminescence not reported in literature can be noted when this gas is present.
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Medição da velocidade de queima laminar de biogás e gás de síntese através do método do fluxo de calor e comparação com mecanismos cinéticosNonaka, Hugo Ohno Barbosa January 2015 (has links)
A velocidade de queima laminar adiabática é um importante parâmetro da combustão que dita o comportamento de chamas pré-misturadas. Dos métodos disponíveis para a medição desse parâmetro, o método do fluxo de calor destaca-se pela simplicidade e precisão. No presente trabalho, esse método é utilizado para medir a velocidade de queima de biogás (modelado como CH4 com diferentes níveis de diluição com CO2) e de gás de síntese (modelado como uma mistura de CH4, H2, CO, CO2 e N2) em ar a 298 K e 1 atm. Tais gases são de crescente interesse para a sociedade em função de aspectos ambientais, porém, suas velocidades de queima não foram amplamente estudadas ainda. Os resultados obtidos são comparados com as previsões de cinco mecanismos cinéticos (GRI-Mech 3.0, Davis et al., Konnov, San Diego e USC Mech II) a fim de avaliar a sua capacidade preditiva. Os resultados experimentais e numéricos das velocidades de queima de biogás e ar apresentam uma boa concordância e as incertezas encontradas foram condizentes com as relatadas na literatura. Os resultados experimentais desse gás foram parametrizados em uma correlação empírica de fácil utilização em modelos numéricos. As medições da velocidade de queima de gás de síntese e ar, por outro lado, apresentaram valores inferiores às previsões numéricas de todos os mecanismos estudados. Os dados experimentais da literatura, para a mesma mistura, diferem tanto em valores quanto em comportamento dos resultados do presente trabalho. Tal comportamento está provavelmente relacionado a alguma contaminação no CO utilizado, já que quando esse gás está presente observa-se uma chemi-luminescência não relatada na literatura. / The adiabatic laminar burning velocity is an important combustion parameter that dictates premixed flames characteristics. Among the measuring methods available in literature, the heat flux method stands out for its simplicity and accuracy. In the present work, this method is used to measure the adiabatic laminar burning velocity of biogas (modeled as CH4 with different dilution levels with CO2) and syngas (modeled as a CH4, H2, CO, CO2 and N2 mixture) in air at 298 K and 1 atm. Such gases are of growing society interest due to environmental aspects, however, their adiabatic laminar burning velocity have not been widely studied yet. The experimental results are compared to predictions of five kinetic mechanisms (GRI-Mech 3.0, Davis et al., Konnov, San Diego e USC Mech II) to evaluate their predictive capacity. Experimental and numerical results of biogas/air mixtures adiabatic laminar burning velocity show good agreement and the found uncertainties are in agreement with literature. Experimental results of this gas were fitted in an empiric correlation of simple numerical application. Experimental results of the laminar burning velocity of syngas/air, on the other hand, show lower values than the numerical predictions of all studied kinetic mechanisms. Literature available data for the same mixture differ both in values and behavior of the present work results. Such behavior is probably related to some contamination on the CO used since a chemi-luminescence not reported in literature can be noted when this gas is present.
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Isotope hydrogeology and geothermal applications to clarify the origin, the sustainability and the character of groundwater flow : examples of the Bohemian and Aquitaine sedimentary basinsJiráková, Hana 13 April 2011 (has links)
Les études isotopiques couplées avec des informations géothermiques peuvent constituer des outils pertinents pour l’exploration des eaux souterraines en tant que ressources en eau potable ou géothermiques. Ce travail combine les deux approches, isotopes de l’environnement et radioactifs associés à des données de température sur des aquifères profonds, dans l’objectif d’enrichir et d’améliorer la connaissance des mécanismes de recharge (Bassin d’Aquitaine, France) ainsi que des mécanismes de recharge et du potentiel géothermique (Bassin Crétacé de Bohème, République Tchèque).Les isotopes stables (18O, 2H, 13C) utilisés conjointement avec des radioisotopes (14C, 3H) sont utilisés pour estimer l’époque de la recharge ainsi que les conditions climatiques qui prévalaient lors de l’infiltration depuis la fin de Pléistocène jusqu’à nos jours. Définir le type de recharge et les conditions d’écoulement est nécessaire pour parvenir à modéliser de façon satisfaisante et fiable les grands systèmes aquifères profonds. Trois types de recharge ont été définis en Europe - (i) continue, (ii) interrompue lors du dernier maximum glaciaire (LGM) – un troisième type (iii) correspond à des situations particulières de recharge.Les conditions géographiques et climatiques très différentes rencontrées en France et en République Tchèque ont engendrées une importante hétérogénéité des conditions et processus de recharge. Le sud de la France, avec un climat relativement doux depuis les derniers 40 ka BP, n’a pas enregistré d’interruption de la recharge. Le temps de séjour des eaux souterraines en Bohème est estimé à environ 11 ka BP au maximum. Cependant, l’appauvrissement des teneurs en isotopes stables enregistré suggère une recharge liée à la fonte de la calotte glaciaire Nord Européenne après le dernier maximum glaciaire (LGM), autour de 18-20 ka BP. Des investigations sur les isotopes du carbone minéral dissous des eaux souterraines du bassin de Bohème ont montrées d’importantes interactions avec différentes sources de carbone qui ont été identifiées.Pour le site d’étude tchèque, les informations apportées par la géochimie ont été complétées par des données géothermiques afin d’améliorer la connaissance des flux et de la dynamique des eaux souterraines. Plus d’une centaine d’enregistrements diagraphiques de température ont été utilisés pour estimer le gradient géothermique. Plusieurs phénomènes viennent perturber le gradient géothermique de la région. Les flux d’eau souterraine verticaux et les variations lithologiques et topographiques sont à l’origine d’une distribution complexe du flux de chaleur, étant majoritairement conditionné par les écoulements souterraines. Les discontinuités peu profondes et les nombreux pointements volcaniques exercent aussi une influence importante sur l’écoulement souterrain et donc aussi sur le potentiel géothermique du réservoir. Les investigations sur la géothermie ont ainsi fourni des informations fondamentales sur le potentiel géothermique mais aussi sur les conditions d’écoulement des eaux souterraines. La prise en compte de ces informations s’avère nécessaire afin de proposer des modèles mathématiques d’écoulement réalistes. / Isotopic investigations combined with geothermal applications represent powerful tools for the exploration of groundwater potential as a drinking or geothermal resource. This Ph.D. thesis combines both approaches, environmental and radioactive isotopes together with temperature data in deep aquifers, in order to enrich and update the knowledge concerning the aquifer recharge processes in the Aquitaine Basin (France) and the aquifer recharge processes and geothermal potential in the Bohemian Cretaceous Basin (Czech Republic).Stable isotopes (18O, 2H, 13C) combined with radioisotope data (14C, 3H) are used to estimate the recharge timing and climatic conditions prevailing during the infiltration from the Late Pleistocene up to modern time. The character of groundwater recharge and regime are necessary to generate relevant source data for the accurate modelling of complex groundwater systems. Three groups of groundwater recharge types can be distinguished throughout Europe – (i) continuous recharge and (ii) interrupted recharge during Last Glacial Maximum and (iii) a group corresponding to particular recharge conditions.The contrasted geographic and climate conditions at both study sites in France and Czech Republic have entailed a great heterogeneity of the recharge conditions and processes. Southern France, with generally mild climatic conditions during the last 40 ka BP, did not experienced considerable hiatus in groundwater recharge. The residence time of groundwater in the Bohemian aquifers is estimated about 11 ka BP at the maximum but the depletion in the stable isotopes suggests that this groundwater originates in the melting of the north European ice sheets after the Last Glacial Maximum period, i.e. 18-20 ka BP. Further investigations on both stable and radioactive carbon isotopes indicated numerous groundwater interactions within the reservoir that were used to delineate the carbon origin within the Bohemian aquifers.Information on groundwater geochemistry was supplemented in the Czech case study by geothermal data in order to improve our knowledge of groundwater flow and dynamics. More than a hundred of temperature records from well-logging measurements were used to assess the geothermal gradient in the Bohemian Cretaceous Basin which is the most promising heat accumulation within the country. Many phenomena can affect the thermal field in the region. Vertical groundwater flow and variations in the lithology and the topography lead to a complicated areal distribution of the geothermal gradient and the heat flux which is dominantly controlled by groundwater. Shallow tectonic structures and numerous volcanic rocks exercise an influence on groundwater flow and therefore exert a secondary effect on the thermal field. The geothermal investigation provided useful information on the geothermal resources within the region but also represents an important tool for understanding groundwater flow, and for constructing realistic hydrogeological models in such a complex geological, tectonic and geothermal context.
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Konstrukční návrh části zařízení pro studijní účely krize varu / Design concept of the facility part for the educational objectives of the boiling crisisSuk, Ladislav January 2012 (has links)
Graduation these deals with investigation of critical heat flux in pressurized water nuclear reactors. Theoretical part covers fundamental terms from area hydrodynamics of two-phase flow and critical heat flux. Here are also mentioned the individual approaches to description of physical process of heat transfer crisis. Practical part is devoted to systems design of measuring stand for critical heat flux in vertical canal allowing visualization of two-phase flow.
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Charakteristické parametry procesu spalování při využití vzduchu s obsahem kyslíku vyšším než 21 % / Characteristic parameters of oxygen-enhanced combustion processHudák, Igor January 2013 (has links)
Diplomová práce se zabývá spalováním zemního plynu při využití vzduchu s vyšším obsahem kyslíku (21–46 % kyslíku ve spalovacím vzduchu), tzv. kyslíkem obohaceným spalováním (OEC). Technologie OEC nalezla uplatnění v průmyslu, kde se jsou nároky na zvýšenou produktivitu, dosažení vyšší tepelné účinnosti, zlepšení vlastností plamene, snížení náklady, či zlepšení kvality výsledného produktu. Ačkoliv OEC přináší řadu výhod, je nutné zmínit i nevýhody jako: poškození zařízení, nestejnoměrné zahřívání, narušení plamene, zvýšené emise anebo zpětný zášleh plamene. Zkoušky proběhly na zkušebně hořáků, která umožňuje testovat hořáky nejen na plynná a kapalná paliva, ale i hořáky navržené pro kombinované spalování při maximálním výkonu hořáku 1 800 kW. Při zkouškách byl použit plynový „low-NOx“ hořák se stupňovitým přívodem paliva. V diplomové práci je popsán vliv obsahu kyslíku ve spalovacím vzduchu na emise oxidů dusíku (NOx), teplotu plamene, přenos tepla ze spalin do stěn spalovací komory, a také vlastnosti plamene, zvláště pak jeho stabilitu, tvar a rozměry. Zkoušky proběhly při výkonech 300 kW, 500 kW a 750 kW, přičemž pro výkon 750 kW proběhly testy jak při jednostupňové, tak dvoustupňové konfiguraci.
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Projekční návrh ohříváků topné vody pro výměníkovou stanici 200 MW / Design of heating water heat exchanger, capacity 200 MWVašíček, Jakub January 2014 (has links)
The thesis is focused on the design proposal of thermal heaters for heating water in heat-exchanger station with a total output of 200 MW. The aim of the work is conceptual design of heat exchangers, thermal and hydraulic design of individual heaters and preview of flow of mass and energy. The outputs of the work are written calculations, design drawing of one heater and design of a heater arrangement in exchanger station. The objectives of the work are filled completely. The work is focused on issues directly related to the actual design of heat exchangers, does not give a general overview of the topic. Thermal calculation is limited to the calculation of heat transfer surfaces for condensation of steam and condensate hypothermia.
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Tepelný tok plazmatu na pevné struktury v tokamacích / Plasma Heat Flux to Solid Structures in TokamaksVondráček, Petr January 2019 (has links)
Plasma Heat Flux to Solid Structures in Tokamaks Petr Vondráček Energy and particle exhaust is the key issue for future fusion reactors based on magnetic plasma confinement, namely for tokamaks. Good understanding of processes controlling plasma heat fluxes impinging the first wall of tokamaks is of a main concern for fusion research. This doctoral thesis is focused on experimental investigation of plasma heat fluxes in different locations of the COMPASS tokamak. A new infrared thermography system was built for this purpose as a part of this PhD research. There are four main topics studied using the system. First of all, a narrow near-SOL heat flux channel with a very steep radial profile is characterised in HFS limited discharges. It is shown that the near-SOL heat flux decay length is consistent with the drift-based model of the SOL heat transport. Secondly, heat loading of leading edges of misaligned limiters is broadly studied. The optical approximation of the heat flux distribution around a poloidal leading edge is confirmed as a valid approach. Heat loading of a magnetically shadowed side of a toroidal limiter gap is observed experimentally for the first time confirming predictions of particle-in-cell code simulations. Thirdly, localised hot-spots caused by the impact of runaway electrons as well as...
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Biomass gasification under high solar heat flux / Gazéification de biomasse sous haute densité de flux solairePozzobon, Victor 17 November 2015 (has links)
L'énergie solaire concentrée est une source d'énergie alternative pour la conversion thermochimique de biomasse en vecteurs énergétiques ou en matériaux à haute valeur ajoutée. La production d'un gaz de synthèse à partir de biomasse lignocellulosique en est un exemple, de même que la production de résidus carbonés à propriétés contrôlées. Ces travaux portent sur l'étude du comportement d'un échantillon de hêtre thermiquement épais sous de hautes densités de flux solaire (supérieures à 1000 kW/m²). Deux approches ont été développées en parallèles : une étude expérimentale et le développement d'un modèle numérique. Les expériences ont permis de mettre en lumière le comportement particulier du hêtre sous de hautes densités de flux solaire. En effet, un cratère de char, dont la forme correspond à celle de la distribution du flux incident, se forme dans l'échantillon. Cette étude a aussi montré que la teneur en eau initiale de la biomasse a un fort impact sur son comportement. Les échantillons secs peuvent atteindre un rendement de conversion énergétique de 90 %, capturant jusqu'à 72 % de l'énergie solaire incidente sous forme chimique. Quant aux échantillons humides, ils produisent nettement plus d'hydrogène, au prix d'un rendement de conversion énergétique aux alentours de 59 %. De plus, le craquage thermique et le reformage des goudrons produits par la pyrolyse sont rendus possibles par les températures atteintes (supérieures à 1200 °C) et la présence d'eau. Enfin, il a été montré que l'orientation des fibres du bois n'a qu'un impact mineur sur son comportement. En parallèle, une modélisation des transferts couplés chaleur matière et des réactions chimiques mis en jeu lors de la gazéification solaire d'un échantillon a été développée. La construction du modèle a mis en avant la nécessité de recourir à des stratégies innovantes pour prendre en compte la pénétration du rayonnement dans la matière ainsi que la déformation du milieu par la gazéification. Les prédictions du modèle montrent un bon accord avec les observations expérimentales. Elles ont ainsi permis de mieux comprendre les couplages mis en jeu lors de la dégradation de biomasse sous haute densité de flux solaire. De plus, des analyses de sensibilités ont révélé que les modèles de type Arrhenius ne permettent pas de décrire finement le comportement de l'eau à l'intérieur de l'échantillon et que le choix du modèle de pyrolyse était capital pour décrire correctement le comportement la biomasse sous haute densité de flux solaire. / Concentrated solar energy is as an alternative energy source to power the thermochemical conversion of biomass into energy or materials with high added value. Production of syngas from lignocellulosic biomass is an example, as well as the production of carbonaceous residues with controlled properties. This work focuses on the study of the behaviour of a thermally thick beech wood sample under high solar heat flux (higher than 1000 kW/m²). Two approaches have been undertaken at the same time: an experimental study and the development of a numerical model. Experiments have highlighted a specific behaviour of beech wood under high solar heat flux. Indeed, a char crater, symmetrical to the incident heat flux distribution, forms in the sample. This study has also shown that biomass initial moisture content has a strong impact on its behaviour. The dry sample can achieve an energetic conversion efficiency of 90 %, capturing up to 72 % of the incident solar power in chemical form. While, high initial moisture content samples produce more hydrogen, at the price of an energetic conversion efficiency around 59 %. Furthermore, tar thermal cracking and steam reforming are enabled by the temperatures reached (higher than 1200 °C) and the presence of water. Finally, wood fiber orientation has been shown to have only a minor impact on its behaviour. At the same time, a modelling of the coupled reactions, heat and mass transfers at stake during solar gasification was undertaken. The development of this model has highlighted the necessity to implement innovative strategies to take into account radiation penetration into the medium as well as its deformation by gasification. Numerical model predictions are in good agreement with experimental observations. Based on the model predicted behaviour, further understanding of biomass behaviour under high solar heat flux was derived. In addition, sensitivity analyses revealed that Arrhenius type models are not fitted for precise intra-particular water behaviour description and that the choice of the pyrolysis scheme is key to properly model biomass behaviour under high solar heat flux.
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CROPS WATER STATUS QUANTIFICATION USING THERMAL AND MULTISPECTRAL SENSING TECHNOLOGIESYan Zhu (12238322) 20 April 2022 (has links)
<p>Thermal and multispectral imagery can provide users with
insights into the water stress status and evapotranspiration demand of crops.
However, traditional platforms, such as satellites, for these thermal and
multispectral sensors are limited in their usefulness due to low spatial and
temporal resolution. Small unmanned aircraft system (UAS) have the potential to
have similar sensors installed and provide canopy temperature and reflectance
information at spatial and temporal resolutions more useful for crop
management; however, most of the existing research on the calibration or the estimation
of water status were established based on the satellite platforms either for
the sensors calibration or water status quantification. There is, therefore, a
need to develop methods specifically for UAS-mounted sensors. In this research,
a pixel-based calibration and an atmospheric correction method based on
in-field approximate blackbody sources were developed for an uncooled thermal
camera, and the higher accurate vegetative temperature acquired after
calibration was used as inputs to an algorithm developed for high-resolution
thermal imagery for calculating crop latent heat flux. At last, a thermal index
based on the Bowen ratio is proposed to quantify the water deficit stress in a
crop field, along with this, a method for plot-level analysis of various
vegetation and thermal indices have been demonstrated to illustrate its broad
application to genetic selection. The objective was to develop a workflow to
use high-resolution thermal and multispectral imagery to derive indices that
can quantify crops water status on a plot level which will facilitate the
research related to breeding selection.</p>
<p>The camera calibration method can effectively reduce the
root mean square error (RMSE) and variability of measurements. The pixel-based
thermal calibration method presented here was able to reduce the measurement
uncertainty across all the pixels in the images, thus improving the accuracy
and reducing the between-pixel variability of the measurements. During field
calibration, the RMSE values relative to ground reference targets for two
flights in 2017 were reduced from 6.36°C to 1.24°C and from 4.56°C to 1.32°C,
respectively. The latent heat flux estimation algorithm yields an RMSE of 65.23 W/m<sup>2</sup>
compared with the ground reference data acquired from porometer. The Bowen
ratio has a high correlation with drought conditions quantified using the soil
moisture index, stomatal conductance, and crop water stress index (CWSI), which
indicates the potential of this index to be used as a water deficit stress
indicator. The thermal and multispectral indices on a plot level displayed will
facilitate the breeding selection.</p>
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