New articles of HUNGARIAN AGRICULTURAL ENGINEERING
List of accepted articles to Issue No. 43/2024
1. FINITE ELEMENT METHOD (CFX) INVESTIGATION OF THE FLUID FLOW DISTRIBUTION BEHAVIOR OF BOTH PARALLEL AND COUNTER TYPES OF HEAT EXCHANGERS
Author(s):
S. Hailemariam, J. Beke, I. Oldal, G. Kalácska
Abstract: The thermal heat transfer behavior of hot and cold fluids within boundary conditions on both parallel and counter types of heat exchangers was investigated in this work using the computational fluid dynamics (CFD) approach in ANSYS Workbench (CFX). This technique helps us identify the precise values for the velocity, pressure, and temperature readings along and across the heat exchanger, in addition to determining how the three variables were distributed locally or globally. Cold water at 5 m/s and 20 °C, with a zero pressure at outlet or zero gauge pressure at outlet, was employed in this study, as was hot water at 4 m/s and 90 °C, with the zero pressure at outlet or zero gauge pressure at outlet. The results of any local or global temperature, pressure, and velocity values were represented along the length of both parallel and counter types of heat exchangers by color contours, where red indicated the largest value and blue the lowest. All of the global temperature, pressure, and velocity distributions were shown by charts positioned along the length of both parallel and counter-type heat exchangers. We came to the conclusion that when hot inlet fluid passes between the head and outer surface of cold fluid, there is a T-junction where high pressure and low velocity coexist. In comparison to parallel flow, the pressure and velocity distributions are lower in counter flow.
Keywords: ANYSY (CFX), CFD, heat transfer, pressure, temperature, thermal
Author(s):
S. Kassebi, P. Korzenszky
Abstract: This research explores the interplay between weight loss, color transformation, and total soluble solids (TSS) in Golden Delicious apples during storage at room temperature. Across six weeks, a freshly harvested batch of Golden Delicious apples underwent scrutiny in a controlled environment, maintaining around 24⁰C and 60% humidity. The study aimed to unravel the post-harvest physiological shifts in apples, explicitly focusing on factors affecting consumer appeal and shelf life. Methodologically, weight loss was precisely tracked using a high-precision scale, while color alterations were quantified via a portable colorimeter, yielding CIELAB L*, a*, and b* values. A refractometer was used to assess TSS, which indicated sweetness and ripeness. Correlation analysis revealed a strong link between weight loss and color shift, with a less pronounced yet significant connection between TSS and the other variables. These findings enrich our comprehension of the post-harvest dynamics of Golden Delicious apples, carrying implications for adequate storage and marketing tactics. This research supports the principles of the circular economy by enhancing the efficiency of post-harvest processes and minimizing waste through better storage practices. By understanding these factors, producers can reduce spoilage and extend the shelf life of apples, contributing to more sustainable food systems.
Keywords: Apple, post-harvest changes, storage impact, correlation, mass loss
3. OPTIMAL MATERIAL FLOW CHANNELS OF CROSS FLOW DRYERS
Author(s):
I. Keppler, A. Bablena
Abstract: Reducing the moisture content of harvested grains is crucial for their subsequent processing or storage. Given the substantial energy requirements and potential environmental consequences associated with artificial drying, it is imperative to optimize the efficiency of this process. The quality of the final product is significantly impacted by inadequate or excessive drying, which is heavily influenced by the duration of grain exposure to the drying environment. Advances in dynamic modeling, facilitated by enhanced computational capabilities, have empowered researchers to intricately examine particle movement phenomena within drying equipment. In our study, we investigate variations in particle residence times under diverse geometric and tribological boundary conditions.
Keywords: granular materials, discrete element method, cross flow dryers, particle flow unevenness
Author(s):
A. Kári-Horváth, Zs. Lantos, Á. Sztancsek
Abstract: Towards the middle of the XXI. century, environmental protection is becoming more and more of a focus in the world. According to not only environmentalists but also many politicians, economists, and even historians, the biggest threat to the world is environmental pollution and climate change caused by global warming. Accordingly, the development of environmentally friendly technologies, which does not only apply to the automotive industry, is also in full swing in the transport industry. Much attention is paid to reducing the environmental burden of shipping as well. This is all the more justified since nowadays, the most common ship fuel, the so-called heavy oil, contains 3500 times more sulfur than conventional diesel fuel. Accordingly, there are now floating hotels operating around the world that use LNG as a green fuel. In this article, we try to collect the literature strongly related to the topic in order to develop detailed technology in our further work.
Keywords: shipboard waste, waste utilization, MARPOL convention, Rankine-Clausius cycle, heat treatment technologies
5. OPTIMIZING THERMAL MANAGEMENT IN PHOTOVOLTAIC PANELS: EXPERIMENTAL STUDY
Author(s):
H. Saadi, P. Hermanucz
Abstract: This study investigates the enhancement of thermal management in photovoltaic (PV) systems by implementing a modified setup with copper pipes and an aluminium-based adhesive to boost thermal conductivity. Conducted over a four-month period at the Hungarian University of Agriculture and Life Sciences, the research examined the impact of varying cooling flow rates, insulation levels, and inlet temperatures on the working temperature of a modified PV system. Findings demonstrate that full insulation significantly raises working temperatures up to 67%, while lower inlet temperatures and increased cooling flow rates effectively decrease them to 11,54% and 18,97% respectively. The results suggest that optimizing thermal management can enhance PV efficiency in high-temperature environments, promoting the system’s resilience and efficiency in diverse climatic conditions.
Keywords: photovoltaic systems, radiation, insulation, inlet temperature, flow rate
6. BEZIER CURVE SHAPED LAMELLAE IN CROSS FLOW DRYERS
Author(s):
I. Keppler
Abstract: Recent advancements in dynamic modeling, supported by improved computational technologies, have enabled detailed investigations of particle motion within drying equipment. Under and over drying of harvested crops causes significant financial losses in agriculture. To overcome this issue, we analyzed the particle motion in cross flow dryers using analytical and numerical modeling techniques. In our earlier work we determined the theoretically optimal lamella geometry shape, using the Brachistochrone problem and finding the cycloid curve. The manufacturing problems of creating an approximate cycloidal curve for our experimental investigations showed us that it is not a simple task to solve. To overcome this issue, we investigated the possibility of using other geometries close to the original cycloidal one. This study explores the influence of Bezier curve-shaped lamellae on particle residence time. By examining various geometries and tribological parameters, the research aims to identify an optimal lamella design that minimizes under- or over drying while maintaining ease of manufacturing.
Keywords: agricultural particulate materials, discrete element method, cross flow dryer, flow unevenness, geometry optimization
Author(s):
F. Sampaio, Z. Bártfai
Abstract: The incorporation of robotics in agriculture embodies a major advancement in information and communication technologies, which addresses critical challenges such as promoting sustainability, Labor shortages, and increasing efficiency. This bibliometric analysis explores the trends and patterns in the research development of agricultural drones from 2000 to 2023, against the backdrop of their increasing integration into modern agricultural practices. Agricultural drones, also known as unmanned aerial vehicles (UAVs), have emerged as transformative tools in precision farming, offering capabilities such as crop monitoring, pest management, and soil analysis with unprecedented efficiency and accuracy. This study employs the R-bibliometrics package, Vos Viewer, and Excel for comprehensive analysis, leveraging these tools to examine publication trends, citation impacts, author collaborations, and keyword co-occurrences across a diverse range of journals and disciplines. Findings reveal a steady growth in research output, punctuated by significant peaks in interest, particularly following advancements in artificial intelligence applications within the field. This analysis not only highlights the pivotal role of agricultural drones in shaping modern agriculture but also identifies critical areas for future research and innovation, including AI integration, environmental sustainability, and the optimization of drone technologies for enhanced agricultural productivity and sustainability.
Keywords: Agricultural drones, Precision Agriculture, UAVs, Artificial Intelligence, remote sensing
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