List of papers presented
Dear Colleagues,
We would really thank you all for attending the "Thermal/infrared technologies, fluid flow and heat transfer processes (TITeFHeT)" WSEAS session in Salerno organized under the 10th WSEAS International Conference on Applied and Theoretical Mechanics (MECHANICS '14). We aim that you experienced both academic benefits and a pleasant stay visiting the beautiful surroundings.
In the following, the list of papers presented is given for the records.
Kind regards,
Fisciano, June 7th, 2014
Gennaro Cuccurullo, Giacomo Viccione.
- Plenary Lecture and Paper: Advancement the Monte-Carlo Procedures to be Used by Calculation the Radiative Heat Transfer within Power/Industrial High-temperature Combustion Chamber
Boris Soroka, Vladimir Zgurskyi
Abstract - The advanced stochastic Monte – Carlo (MC) technique has been developed to predict resulting heat fluxes and / or unknown detailed local temperature profiles within the combustion or furnace chambers for arbitrary initial conditions (design and process parameters). Theoretical background is based upon original combination of following constituents: Hottel’s zone method accompanied by his radiation model of weighted sum of grey gases on emissivity / absorptivity for combustion products while executive procedure being performed by means of application the MC counter operating with dozen thousands of random beams related to each of surface or volume zones. Direct thermal and indirect combustion kinetics characteristics have been used as the checked parameters by verification the MC procedures. Validation of the proposed MC procedures have been carried out by means of comparison of our prediction results by physical and chemical characteristics with respective experimental (measured) and literature data for some types of the industrial furnaces and boilers. Because of strong influence of temperature factors on NOx formation by combustion we have succeeded to calculate the temperature profiles and NOx issue by recirculation the combustion products under operation the boilers of different types. These data confirm an opportunity to predict the pollutants formation values being fairly coincided with measured data.
- A Dynamic Model for Building Heating Plants
Davide Borelli, Simona Repetto, Corrado Schenone
Abstract - Current EU energy policy pursues the reduction of fossil fuels consumption, both by increasing the use of renewable sources, both by optimizing the use of the energy through actions that involve the different fields (buildings, transports, lighting, heating and cooling, etc.). In particular, the area of the heating/cooling is a key sector, since about 30% of energy consumption in the EU countries is addressed to the thermal comfort in buildings. A relevant role can play in this sense a more efficient management of the heating plants, with a better use of the electronics and smart setting strategies. In order to get these goals a dynamic approach to the analysis of the heating plant is due, since only the knowledge of the transient behavior of the diverse elements of the plant can lead to successful energy saving actions. Aim of the present study is to develop a dynamic model for building heating plants able to simulate the time history of some key parameters and describe the behavior of the system for varying boundary conditions. The model has been validated through the comparison with a set of experimental data referring to a 5 storey single building made of 20 apartments. In spite of some rough assumptions, simulated and measured temperature curves show a good agreement.
Keywords: Heating plants; Plants dynamic modelling; Building energy simulation; Thermal analysis.
- A Quantitative Infrared Thermography Method for the Assessment of Windows Thermal Transmittance
Francesco Bianchi, Giorgio Baldinelli, Francesco Asdrubali
Abstract - The window is one of the weakest elements of buildings envelope and it is characterized by three-dimensional heat exchange that makes its study, in terms of overall thermal performance, quite complex. The thermal field on window surface is defined by different parts such as transparent zone (glass) and frame (wood, aluminum or PVC) and their matching generates thermal bridges, downgrading the insulation properties of the entire window. The hot box test is a laboratory setup which allows the evaluation of the window thermal transmittance; the paper shows the comparison between the results obtained by hot box measurements and the thermal transmittance assessed by an original experimental methodology based on quantitative infrared thermography, conducted on a wooden window.
Keywords: depth-averaged models, granular flows, two-layer models, dam-break, avalanche, debris flows.
- 'Classical' Thermal NDT of Hidden Defects: Passing from Defect Detection to Defect Characterization
V. P. Vavilov, A. O. Chulkov, D. A. Derusova
Abstract - The goal of this study is the analysis of some candidate defect characterization parameters in application to detection of impact damage in carbon fiber reinforced polymers. It is shown that quantitative evaluation of 'defectivity' aimed to further estimation of material strength, or lifetime, should be done by determining material thermal properties. Experimental results obtained are related to active thermal nondestructive testing of aviation panels with impact damage. The efficiency of some image processing algorithms, such as principal component analysis, Fourier and wavelet transform, has been evaluated. It has been found that the result of image sequence processing should be an image of diffusivity in a two-sided procedure and image of effusivity in a one-sided procedure.
Keywords: thermal nondestructive testing, heat conduction, effusivity, diffusivity, image processing.
- Cooling of a Multi-Chip Power Module
G. Cammarata, G. Petrone
Abstract - This paper is aimed at numerically investigate on thermal behavior of an electronic multi-chip power module. Because of the high level of thermal power to be dissipated during functioning, and in order to avoid dangerous overheating, the device is equipped by a cooling system. It mainly consists in pin-fins baseplate plunged in a water stream. A FE-based model is used to solve the fluid flow and the conjugate heat transfer problem. Velocity and pressure fields are computed by adopting a RANS approach coupled with a standard k-eps closure scheme for turbulence solution. Results are mainly presented in terms of velocity fields, temperature for outgoing fluid, die average temperature and pressure drops. A parametrical analysis is presented, in order to elucidate influence of inlet conditions of the cooling water on global thermal performance for the system.
Keywords: Heat transfer, cooling, electronic device, power module, numerical, FEM.
- Experimental Investigation on the Effect of Aluminum Foam on Natural Convection in Horizontal Channel Heated Below
Oronzio Manca, Sergio Nardini, Bernardo Buonomo, Lorenzo Marinelli, Claudio Montaniero
Abstract - Natural convection of air in horizontal parallel plates without and with aluminum foam is experimentally and numerically investigated. The lower wall is heated at uniform heat flux and the upper parallel plate is not thermally insulated to the external ambient. The investigation is carried out by means of a visualization technique and heated wall temperature measurements. The investigated aluminum foam had 10 and 30 Pores per Inches (PPI). The considered configurations are compared and it is found that the presence of the aluminum foam determines a better thermal heat transfer with respect to the clean channel with a low emissivity whereas higher heated wall temperature values with respect to the clean channel with the heated lower plate at high emissivity. Flow visualization is carried out to detect the development and the shape of the main flow and the transitions along the channel. Results of the visualization allow the description of secondary motions inside the channel.
Keywords: Natural convection, Aluminum foams, Horizontal channel, partially filled with porous foam.
- Heat transfer Enhancement for Cooling Electronic Boards using Ultrasonic Waves: Preliminary Remarks
C. Bartoli, M. Macucci
Abstract - In this contribution we take into consideration the effect of ultrasounds on thermal exchange. Since 2008, in the thermofluidynamics laboratory of the DESTeC department basic studies have been performed on this subject. Here, in particular, we move from the investigation of the convective exchange coefficient between a circular cylinder (heated via the Joule effect) and deionized water to a real-life case, where heat is exchanged between transistors and a dielectric fluid. Preliminary experimental data seem to confirm that the presence of ultrasounds induces a significant increase of the convective exchange coefficient in subcooling boiling conditions.
Keywords: Heat transfer enhancement, ultrasound wave, subcooling boiling condition, dielectric fluid.
- Local Thermal Non-Equilibrium in Mixed Convection in Channels Partially Heated at Uniform Heat Flux Filled with a Porous Medium
Bernardo Buonomo, Oronzio Manca, Paolo Mesolella, Claudio Montaniero, Sergio Nardini
Abstract - A numerical analysis of mixed convection in a vertical channel filled with metal foam partially heated at uniform heat flux is studied numerically. Local thermal non-equilibrium and Brinkman-Forchheimer extended Darcy model are assumed. Boussinesq approximation with constant thermophysical proprieties are considered. Results are carried out for an aluminium foam with 10 pore per inch (PPI) and ε=0.909, the fluid is air. Results, for different Reynolds numbers and geometrical aspect ratios, are given in terms of solid and fluid temperatures, at heated walls and inside the channel at several heights, velocity profile along the channel, local and average Nusselt numbers. Results show that diffusive effect resulted lower temperature values inside the solid and the fluid temperatures are higher in all considered cases. For heated channel with smaller aspect ratios, an average Nusselt number increase is found for solid and fluid phases.
Keywords: Mixed Convection, Vertical Channel, Partielly Heated, Porous Media, Local Thermal, Non_Equilibrium, Numerical.
- Looking Inside a Microwave Oven for Continuous Flow Heating by IR Thermography
Gennaro Cuccurullo, Laura Giordano, Giacomo Viccione
Abstract - A first attempt for on-line quantitative IR-thermography temperature readout has been performed inside an illuminated microwave oven. The main aim was to feature bulk temperature profiles in laminar pipe flow. The proposed procedure is intended to overcome the well-known difficulties connected with temperature retrieval while microwave (MW) heating occurs, while promoting high spatial resolutions. In fact, temperature measurements are usually taken onto few points by means of fiberoptic probes. Such an approach is often inadequate for properly controlling the process at hand, as strongly uneven spatial distribution of the temperature field is expected as a consequence of the electromagnetic distribution inside the cavity. Considering theoretical results already obtained by the authors, a linear distribution of the bulk temperature was realized for high water flow rates occurring in a circular pipe exposed to MW heating. Such an occurrence allowed a proper preliminary calibration based on which, a procedure for processing infrared images in real time is proposed. Experimental results related to two temperature levels, namely 40 and 50 °C, and two flow rates, that is 4 and 5.7 g/s, are reported. Experimental values of bulk temperature were compared with numerical results obtained by applying a 3D FEM model, developed by the authors, accounting for constant dielectric and thermal properties. A quite satisfying agreement between experimental and numerical data was found, retrieving better results with increasing flow rates.
Keywords: Microwave heating of liquids, Maxwell’s equations, Numerical modelling, FEM, CFD, Comsol multiphysics, Experimental validation, Infrared thermography.
- Particles Dispersion in a Stratified Turbulent Ekman Boundary Layer
Pietro Scandura, Vincenzo Armenio
Abstract - Particle dispersion in a stratified bottom Ekman layer is studied by direct numerical simulation. Neutral, stable and unstable stratifications are considered. The stable stratification tends both to suppress the turbulence and to reduce the boundary layer thickness, while the opposite is observed for the unstable case. Therefore stable stratification inhibits vertical dispersion of particles, whereas unstable stratification gives rise to a rapid dispersion of particles in the vertical direction. We show that besides having a strong influence on the diffusion along the vertical, stratification also affects particle dispersion along the horizontal directions.
Keywords: Ekman layer, turbulence, stratification, particles dispersion, diffusion coefficient, numerical simulation.
- Preliminary Experimental Results and Performance Analysis of Hybrid Retrofitted Photovoltaic Panels
Cecilia Rossi, Mattia De Rosa, Vincenzo Bianco, Federico Scarpa, Luca A. Tagliafico
Abstract -The aim of present study is to investigate different methodologies to retrofit photovoltaic modules (PV), in order to ensure a good cooling effect by adding a thermal plate in the back side of the PV panel to collect heat, thus obtaining a thermal photovoltaic module (PVT). The most promising perspective of this technology is to couple it with a heat pump, in order to obtain a photovoltaic thermal solar-assisted heat pump (PVT-SAHP) system.
This work proposes an investigation of three different solutions to retrofit commercial PV panels. A thermography analyses has been performed in order to verify the cooling effect on the PV module. Results show that retrofitting of existing photovoltaic panels represents an interesting approach in order to employ very simple solutions to increase the overall efficiency of PV system, especially by coupling it with a heat pump. Finally, in order to study the effective potential of this technology, three different system configurations have been compared in terms of primary energy efficiency, namely a photovoltaic solar assisted heat pump (PVT-SAHP), a solar assisted heat pump (PCEA) and an air-to-water heat pump with a separate set of photovoltaic panels.
Keywords: Energy System, Heat Pump, Hybrid panel, PV retrofitting, Thermography, PV-SAHP.
- The Use of Ohmic Heating in Processing of Food Industry
Gianpiero Pataro, Giorgio Donsi’, Giovanna Ferrari
Abstract -The aim of this work was to identify optimal pre-treatment conditions for cannellini beans in order to improve heating uniformity and, thus, the quality of product, during the subsequant sterilization process. Dry beans were blanched for different length of times (35 and 50 s) in a water bath set at 90°C after soaking (12 h) in tap water. Heating curves of solid-liquid mixtures (53g of beans/100g of mixture) of pre-treated beans and salt solution (1 g/100mL) were determined in a static ohmic heating device by applying a constant voltage of 100V. Results showed that the ohmic heating rate of beans increased with increasing the blanching time as a direct result of the increase of electrical conductivity. Optimal pre-treatment conditions, which allowed the ohmic heating of both phases of solid-liquid mixture at comparable rate, were found when beans were blanched for 50 s at 90°C. Beans pre-treated under optimal blanching conditions and sodium chloride solution (1g/100ml) (53g of beans/100g of mixture) were then subjected to both ohmic and in-container sterilization process. The solid-liquid mixture was sterilized at 121 °C for 10, 15 and 20 min. The parameters measured immediately before and after thermal treatments were: total microbial count, yeasts and molds, split degree, and proteins content. The experimental results have shown that, regardless the thermal method and treatment conditions the initial microbial spoilage was reduced up to below the detection limit of the method (<10 cfu/ml). When compared to the beans sterilized by conventional treatment, the samples treated by the ohmic method appeared of attractive appearance, with a lower split degree. The analyses of the chemical composition revealed a higher proteins concentration in sample processed by ohmic heating than those treated by conventional method.
Keywords: Energy System, Heat Pump, Hybrid panel, PV retrofitting, Thermography, PV-SAHP.
- Thermal Modelling of a Skin Tissue for Medical Screening Applications
Maria Strakowska, Boguslaw Wiecek
Abstract -A multilayer layer heat transfer model of a tissue including perfusion is presented in this paper. The model is suited for transient analysis. By using Laplace transform and symmetry of heat transfer, the model could be simplifies and solved analytically. We compare the modeling results with cold-stress experimental data for weak excitations in the frequency domain using the Nyquist plot. The model was applied for thermal parameter estimation of multilayer biological structures and classification of normal and pathological cases.
Keywords: IR thermography, cold-stress, perfusion, heat transfer modelling.