Antonio Delgado

• Dr.-Ing.
• Professor (Full) at Friedrich-Alexander-University Erlangen-Nürnberg

The paper reports a fully resolved numerical simulation of turbulent duct flow developing under complex inlet flow conditions at very low Reynolds number based on the channel width and bulk velocity. Turbulence was initiated by inflectional instabilities created at the duct center owing to the special inlet design. All simulations were performed us...

https://www.sciencedirect.com/science/article/pii/S0360544224039707 Computational Fluid Dynamics is a crucial tool for designing Positive Displacement machines. In this regard, we have developed a Computational Fluid Dynamics in-house solver to predict phase change phenomena inside the chambers of twin-scroll compressors and expanders handling two-...

This investigation aims to elucidate the dissociation of CO 2 gas from gas hydrates (GH) over a 60-minute duration at varying temperatures, with the objective of understanding the entrapment of CO 2 gas within GH with the use of GH promoters. The study examines four food-grade amino acids possessing surfactant capabilities—cysteine, leucine, methio...

Due to the regulation (EU) Nr. 327/2011 for fans, higher and higher efficiencies are required in order to save energy. In the future, low-pressure axial fans in particular will must generally be designed with stator guide vanes in order to achieve the required level of efficiency. The guide vanes can be installed in front of the impeller or behind...

During the design process of low-pressure axial fans, load criteria are often applied to minimize losses and obtain optimal machines. Particularly in the case of decelerated flows, such as in a blade channel of an axial fan, the flow tends to detach and form vortices due to the positive pressure gradient. Exactly 70 years ago in 1953, based on expe...

Microstructured optical fibres (MOFs) are a new type of optical fibres that possess a wide range of optical properties and many advantages over common optical fibres. Those are provided by unique structures defined by a pattern of periodic or quasi-periodic arrangement of air holes that run through the fibre length. In recent years, MOFs have opene...

The present-day diet contains a variety of breads and confectionary types, making bakery products an essential component. Ammonium bicarbonate, a chemical leavening agent used in black-and-white cookies can, however, have unfavourable side effects, such as the production of acrylamide which is a carcinogen. This research aims to use carbon dioxide...

The determination of the drying degree of food residues on surfaces is an important step before efficient cleaning can be achieved. To accomplish this goal, a rapid evaluation based on a neural network and non-invasive measurement technique is introduced. Two common starch-based products and various yogurts from different manufacturers are used as...

Microstructured optical fibres (MOFs) are a new type of optical fibres that possess a wide range of optical properties and many advantages over common optical fibres. Those are provided by unique structures defined by a pattern of periodic or quasi-periodic arrangement of air holes that run through the fibre length. In recent years, MOFs have opene...

Cyclones serve as essential devices in various industries for the removal of particulate matter from gases and liquids, contributing to improved equipment efficiency and longevity by mitigating the wear and damage caused by dust and small particles. Uniflow cyclones offer improved accessibility due to their predominantly horizontal orientation. Thi...

Separation of Tenebrio molitor larvae from unwanted residues, like frass, feed or exuviae is a key process step for an industrial scale plant. One method to separate larvae from residues is using a zigzag air classifier. For designing and for an efficient operation of a zigzag air classifier, the terminal velocity is a key parameter to separate lar...

In this unprecedented study, the application of CO2 gas hydrates (GH) as a leavening agent to produce black-and-white cookies by replacing ammonium bicarbonate is investigated. Ammonium bicarbonate, the principal leavening ingredient in black-and-white cookies, has been linked to the creation of a carcinogenic substance known as acrylamide. Three d...

Cyclones are devices used in various industries to remove particulate matter from gases and liquids. Commonly used in the power generation, cement, and mining industries, cyclones improve the efficiency and longevity of equipment by removing dust and other small particles that can cause wear and damage. Among centrifugal separation, reverse-flow cy...

Due to its “generally recognized as safe status” (GRAS) and moderate treatment temperatures, non-thermal plasma (NTP) has lately been considered a suitable replacement for chemicals in the modification of food properties and for preserving food quality. One of the promising areas for the application of NTP is the treatment of wheat flour, leading t...

This article brings together the application of ice-like CO2 gas hydrates (GH) as a leavening agent in wheat bread along with the incorporation of some natural gelling agents or flour improvers into the bread to enhance the textural properties of the wheat bread. The gelling agents used for the study were ascorbic acid (AC), egg white (EW), and ric...

The aim of this study is to examine how CO2 gas hydrates (CO2 GH) are used in baking, notably in the creation of wheat bread, as a leavening agent. CO2 GH were produced with the use of food grade amino acids called promoters. The article emphasizes an interesting approach by using a hybrid combination of yeast and CO2 GH. The current study is based...

The frothy foam on top of beer is produced by bubbles of gas, predominantly carbon dioxide, rising to the surface. The chemical components that produce the head are wort protein, yeast, and hop residue. This involves a large number of chemical components and numerous physical interactions. The beer foam and, especially, its stability is an essentia...

Methane gas is a fossil clean fuel since the products of the combustion are only carbon hydrate and water. Methane hydrate is a potential source of methane gas. This ice-like methane source can be found in deep seafloors and permafrost regions, characterized by high pressure and low-temperature conditions. In this work, we simulate the process of m...

Liquid foams exist in a wide variety of chemical and industrial processes, and they can contaminate the end-product and cause time and economical losses. Understanding and simulating foam is not a straightforward task, due to the highly dispersed time and length scales where the physical phenomena occur. Surfactants’ or proteins’ length scales are...

A compressible VoF solver was employed to predict sloshing-induced flow phenomena with and without accounting for the effect of a porous medium situated in various zones inside partially filled tanks. Grid sensitivity studies ensured obtaining grid-independent solutions. The solver, validated against experimental measurements, was employed to syste...

In the presented research, the use and technical realization of CO2 gas hydrate (GH) as a novel baking agent is investigated. GH are ice-like structures where one mole of hydrate typically consists of about 85% water and 15% gas. Hydrates were formed in a lab-scale 1.1 L stirred tank reactor at 1-2°C and 3.5 MPa, and transferred into a temperature-...

Industrial turbomachines, such as fans and blowers for drying, venting, cooling or conveying tasks, are often used in industrial applications and frequently are large energy consumers. Thus, there is a need for further optimization and efficiency increase. For fans and blowers, gaps between moving parts are unavoidable due to manufacturing toleranc...

Gas (guest) molecules are trapped in hydrogen-bonded water molecules to form gas hydrates (GH), non-stoichiometric solids that resemble ice. High pressure and low temperature are typical conditions for their development, with van der Waals forces joining the host and guest molecules. This article study investigates the application of CO2 gas hydrat...

Low-pressure axial fans have a very wide range of applications in the field of heating, ventilation and air conditioning as well as refrigeration (HVAC&R). Due to stricter legal requirements, increasingly higher fan efficiencies are required. Due to legal regulations, more efficient machines are becoming increasingly important. A small gap, the so-...

Low-pressure axial fans have a very wide range of applications in the field of heating, ventilation and air conditioning as well as refrigeration (HVAC&R). Due to stricter legal requirements, increasingly higher minimum fan efficiencies are required. Due to the simpler manufacturing efforts, unprofiled, simply bent sheet metal blades are often used...

Microstructured optical fibres (MOFs) are fibres that contain an array of air holes that runs through the whole fibre length. The hole pattern of these fibres can be customized to manufacture optical devices for different applications ranging from high-power energy transmission equipment to telecommunications and optical sensors. During the drawing...

Due to the gap between the impeller and the casing of a radial fan a gap flow rate occurs, leading to a higher flow rate through the impeller than through the fan. The gap flow rate has an impact on the performance of the radial fan and must be considered in the design process. There is only little known from the literature about the gap flow rate....

Low pressure axial fans have a very wide range of applications in the field of heating, ventilation and air conditioning as well as refrigeration (HVAC&R). Due to stricter legal requirements, increasingly higher minimum fan efficiencies are required. That is why the optimized design of the fan is a crucial point in the development process. Therefor...

Gas to gas diffusion and convection phenomena exists in a wide range of applications include industrial and scientific processes, food production and storage and breathing gases. To analysis gas-gas mixing phenomena, a numerical model based on open-source tool libraries, was developed and validated; an experimental model was built up and repeated p...

Demand to improve food quality attributes without the use of chemicals has risen exponentially in the past few years. Non-thermal plasma (NTP) (also called ‘cold plasma’) is becoming increasingly popular for this purpose due to its unique low-temperature and non-chemical nature. In the present research, the concept of in situ dielectric barrier dis...

The aim of this study is to compare the application of ozone with that of air during the dough kneading process. Experiments were performed on doughs made from two wheat flours of different protein contents by changing the treatment time and oxidative gas. All samples were analyzed by Farinograph, oscillatory rheometer, and dough extensibility test...

Bakery and cereal products are a basic part of today's diet, which includes a wide variety of breads, biscuits, and confectionery varieties. The elastic gluten structure, that is formed during the kneading of flour, can contain the increasing leavening gases produced during rising for any type of baked product. However, some chemical leavening ingr...

Thermoforming is a complex process with numerous parameters that potentially have an influence on the wall thickness distribution of the end product. Test benches do not allow for measuring all potentially relevant influences. Numerical simulations therefore have proven to be a useful tool in order to obtain deeper insight into the process and the...

Unwanted foaming and liquid bridging inside structured packings have a negative effect on the pressure drop during thermal separation processes. A novel helical design of a packing column for preventing foaming is presented. The effective interfacial area is calculated by numerical simulations. Different designs are analyzed by varying geometrical...

The dissociation of CO2 gas hydrates (GH) with amino acid kinetic promoters and without promoters was studied at a high temperature of 90 °C for a period of 20 min to understand the percentage of CO2 gas and to select the best promoter that aids CO2 gas entrapment along with stability at a high temperature. The possibility of using four hydrophobic...

Unwanted foam bears the risk of affecting different thermal industrial processes negatively, by reduced process efficiency, contamination, and total shutdown. Mechanical defoaming methods are difficult to implement, while chemical anti‐foaming agents are challenging in correct dosing. Ultrasonic defoaming actuators destroy foams purely mechanically...

Foam exists in several food and chemical processes. It often delays, contaminates, and obstructs the industrial process, which affects the product's quality and safety. Liquid drainage in foam is one of the most influencing physical phenomena impacting its behavior, and is characterized by its short time scales. The lattice Boltzmann method (LBM) i...

Per- and polyfluoroalkyl substances (PFAS) are omnipresent synthetic chemicals. Due to their industrial importance and widespread use as a key component in various applications and a variety of products, these compounds can be found today in high concentrations (>1 μg/L) in surface and groundwater but also spread throughout the ecosystem, where the...

Due to the increase of the human world population, modern-day research is looking for new methods of protein exploitation. Therefore the authors conducted a joint research project with the goal to automate the breeding of Tenebrio molitor as a novel protein source. An important task is to monitor the size of larvae in order to control the rearing p...

This work deals with the numerical investigation of a three-dimensional, laminar hydrogen-air diffusion flame in which a cylindrical fuel jet is surrounded by in-flowing air. To calculate the distribution of gas molecules, the model solves the species conservation equation for N-1 components, using infinity fast chemistry and irreversible chemical...

The scope of this paper is to present the design and verification of an integrated OpenFOAM membrane fluid-structure interaction (FSI) solver for small deflections, which employs the finite volume method (FVM) for solving the flow field and the finite area method (FAM) for solution of the membrane deflection. A key feature is that both the fluid an...

The authors present a thermally and dynamically coupled fluid–structure‐interaction (FSI) model of a thermoforming process variant along with simulation results. By purposeful arrangement of the inlet nozzles, the process variant under consideration seeks to improve the deformation behavior of a plastic sheet made of polyvinyl chloride (PVC), ultim...

Turbulent drag reduction by an extremely diluted aqueous solution of polyacrylamide was studied in a fully developed plane channel flow under non-tripped flow conditions allowing the natural development of turbulence presumably from the initially laminar like a flow state. Using laser-Doppler anemometry, all components of the Reynolds stress tensor...

Bakery and cereal products are a significant part of the present-day diet comprising a vast range of bread, cookies, and innumerable varieties of confectionaries. Flour when combined with water, forms an elastic gluten structure, which stretches to hold the increasing leavening gases throughout rising for each type of baked item. However, some ingr...

Foams exist in several food processes, where they often delay, disrupt, and contaminate food production, quality, and safety. Although food foams are complicated and high maintenance phenomena, their prevention is necessary to avoid subsequent microbial risks. In so doing, it’s possible to provide healthy final food products and ensure individuals...

The jumping-droplet phenomenon occurring on superhydrophobic (SHPhob) surfaces under special conditions may be beneficial for numerous systems using condensation, due to the reported increased heat transfer coefficients. One technique to create a SHPhob surface is coating, which can be applied to larger areas of existing elements. However, challeng...

A correction to this paper has been published: https://doi.org/10.1007/s00449-021-02594-8

Non-carbonated fruit juices often tend to foam over during bottling. The resulting foam height corresponds to the equilibrium of foam formation and decay. Therefore, the foam unexpectedly occupies more space in the bottle and carries parts of the juice out of the bottle, resulting in product loss under filled containers and hygienic problems in the...

This experimental research was performed for the measurement-based detection and numerical simulation of a biological multiphase flow in a fermentation tank. The difficulties of an investigation are the many complex interactions between the different three phases (yeast as solid, carbon dioxide as gas, wort as liquid). One of the main difficulties...

Bubble columns find wide application as multiphase contactors and reactors in chemical, biochemical , metallurgical, and petrochemical industries due to their ease of operation and maintenance, high heat and mass transfer rates, and low operating and maintenance costs. In those reactors, gas is usually introduced from a sparger at the bottom of a c...

Increase of the efficiency of condensing heat exchangers can be achieved by promoting the dropwise condensation (DWC). It increases the heat transfer coefficient by up to one order of magnitude compared to the filmwise condensation. For jumping-droplet condensation, which takes place on superhydrophobic surfaces, further increase of heat transfer c...

Ever since the potential of algae in biotechnology was recognized, models describing the growth of algae inside photobioreactors have been proposed. These models are the basis for the optimization of process conditions and reactor designs. Over the last few decades, models became more and more elaborate with the increase of computational capacity....

In this work, the effects of a functionalization method involving different conditions and milling processes on the dispersion and thermal and electrical conductivity of multiwalled carbon nanotubes were studied. The surfaces of MWCNTs were modified using a mixture of sulfuric and nitric acid as an acid treatment and potassium persulfate and sodium...

The aptamer, known as a chemical antibody, has proven to be of high diagnostic and therapeutic value with the FDA’s first aptamer drug in 2004 and many aptamers under clinical validation. However, the clinical translation of aptamer for therapeutics has been delayed because of the limitation of using the target model during selection and a lack of...

A novel separator geometry is designed and manufactured to examine the possibility of fine dust separation Therefore the separator and a small wind turbine are mounted into a wind tunnel and tested at different wind speeds While recording the rotational speeds of three different wind turbine blade designs, the blade design and pitch angle with the...

The interaction between fluids and solids is becoming increasingly important in the design and analysis of machines, buildings and systems. Due to the fluid-mechanical phenomenon of turbulence and the associated flow and vortex shedding, the fluid structure interaction must be considered, for example, in aircraft wings, civil engineering (e. g. tel...

The multi-walled carbon nanotubes (MWCNTs) and Alumina (Al2O3) (CNT/Alumina) have been synthesized by two different simple methods including mechanical and chemical fabrication. The effect of the weight ratio of MWCNTs to Alumina on dispersion characteristic and thermal conductivity has been studied. To confirm that it is the success process, the m...

The dynamic contact angle model is applied in the formation process of a series of bubbles from Period-I regime to Period-II regime by using the VOF method on a 2D axisymmetric domain. In the first process of the current research, the dynamic contact angle model is validated by comparing the numerical results to the experimental data. Good agreemen...

The baking process demands a high amount of energy, but only one-third of the total energy supply to the baking oven is actually used for baking, while the rest is dissipated to the environment. This implies that the energy input to the baking process can be significantly reduced, e.g., by enabling a more efficient heat transfer to the product, com...

This study investigates the impacts of different airfoil shapes on the 3D augmentation and power production of horizontal axis wind turbines (HAWTs). The aerodynamic effect from changing the leading and trailing edge of the airfoil is the emphasis of the research. Varied power produced from modifying sensitivity on 3D augmentations, caused by revam...

Over the years, solar collecting systems have gained interest in renewable energy. This study investigated improving the efficiency of the working fluid in thermal solar systems by using nanofluids with three concentrations of alumina, 0.1, 0.3, and 0.5 wt%. The UV-vis absorbance, electronic conductivity, and thermal transfer properties of the nano...

This paper demonstrates the application of artificial intelligence-driven turbomachinery design, its numerical performance predictions and their numerical validation. A common problem in the industrial application of turbomachinery is that readily available turbomachines are not necessarily matching the desired performance targets (performance char...

This paper describes the application of CO2-hydrate technology for the concentration of apple juice towards industrially relevant levels. Assays were carried out in a stirred autoclave at 1–2 °C and 35 bars with rediluted apple concentrate in the range of 11°Bx to 40°Bx. A hydraulic pellet press was used to separate the hydrate from the concentrate...

The present paper takes up the underlying nonlinear initial value problem from a preceding author’s work about the dynamics of a single bubble in a highly viscous liquid medium under different pressure impacts. The arising ordinary differential equation is mainly based on the constitutive relation of a second-order liquid that in particular include...

Wettability, roughness and surface treatment methods are essential for the majority of practical applications, where liquid–solid surface interactions take place. The present study experimentally investigated the influence of different mechanical surface treatment methods on the static wettability of uncoated and amphiphobic-coated aluminium alloy...

The present work aims to validate mid-infrared imaging as a promising method for evaluating oven systems. Therefore, a novel approach by analyzing mid-infrared radiation patterns captured by a thermal camera and subsequent image processing was developed. A thermal camera was adapted to two different oven systems: a standard electric deck oven and a...

This article proposes the novel integration of an advanced configuration of Liquid Air Energy Storage (LAES) plant and an additional gas turbine cycle with an existing large-scale Natural Gas Combined Cycle (NGCC). A novel mode of exploiting the electric energy stored within the LAES plant and additional gas turbine cycle in combination with the ex...

Automating the production of insects for rearing, harvesting and processing is an important step in making insect mass production more attractive, cost effective and competitive. In this study, we present a functional model for the automated separation and monitoring of the breeding process of mealworms. Data have shown that it is possible to separ...

The cultivation of phototropic microorganisms in photobioreactors (PBR) permit to achieve culture densities only in the order of few grams per litre. Consequently, harvesting and downstream processes turn out to be expensive. In order to investigate and maximize process conditions, multiphysics simulations of phototropic cell cultivation are regard...

The trailing edge flow in a centrifugal impeller is of great importance as it determines the exit flow velocity triangle and therefore the work transferred to the fluid. The present study deals with the impact of trailing edge under-filing on the impeller exit flow and the resulting slip factor. Different under-filed trailing edge shapes are invest...

Protein foam dynamics is a complex and challenging topic in food and chemical industry. Protein foams exist in several industrial applications, such as food supply, discharge pipes, dairy products tanks and rectification columns. Foams often influence the mass, momentum and energy transport as well as the bio-chemical reactions. Consequently, this...

The working machines such as fans, blowers and pumps are often used for transporting fluids in technical systems. The rotating impeller is used for energy conversion of mechanical work into hydraulic work. Leonhard Euler published this relation of energy conversion in 1752–1756 and is still used today for the basic design of turbomachinery. In the...

Food industry is worldwide one of the most energy demanding sectors, commonly with the overall primary energy demands among top five industrial branches. Due to the constant population increase, it is reasonable to assume that this tendency will reflect to the future energy demand of the food industry as well. Within the food processing industry, b...

In the fields of aerodynamics and turbomachinery trailing edge flows are of great interest as they can substantially affect performance, vibration and sound emission. The present paper discusses the trailing edge and wake flow in centrifugal pump impellers. In the first part of the study the effect of the trailing edge flow on the performance of eq...

Hydrogen-based mobility and hydrogen storage are gaining increased interest worldwide, due to a global demand for sustainability, use of renewable energy sources and reduction of greenhouse gas emissions. Liquid organic hydrogen carrier (LOHC) systems allow long-distance transport and long-term storage of hydrogen under mild conditions, with a high...

Due to their high production rates of proteins, fatty acids, pigments and other high value cell metabolites, microalgae are a promising resource for the food and feed, cosmetic and pharmaceutical industry. Since the downstream processing contributes largely to the overall production cost of microalgae-based products, new technologies are required t...