Papers by Keyword: Experimental Analysis

Abstract: In this paper, we analyze the thermal performance of a Latent Thermal Energy Storage (LTES) system prototype, consisting of a finned-tube heat exchanger immersed in the paraffinic Phase Change Material (PCM) RT50. With the aim of demonstrating the influence of the fin density on the system thermal performance, experimental tests were conducted by varying the fin pitch while maintaining constant the Heat Transfer Fluid (HTF) operating conditions (i.e., mass flow rate and inlet temperature). The experimental findings indicate that increasing the fin density significantly reduces the charging and discharging process durations up to approximately 5-10 times, consequently improving the average heat transfer rate between the HTF and the PCM.

Abstract: This study explores the integration of thermoelectric generators (TEGs) and phase change materials (PCMs) to enhance the efficiency of photovoltaic (PV) panels in high-temperature conditions. An AP-PM-20 Polycrystalline PV panel, SP-1848-27145 Bismuth Telluride TEG, and paraffin wax PCM in an aluminum container were used. Four configurations were tested: standalone PV, PV-PCM, PV-TEG-PCM, and PV-PCM-TEG, under identical conditions from 10:30 AM to 6:00 PM at 25-minute intervals. Data on PV and TEG voltage, current, and solar irradiance were collected and analyzed. The results show significant performance improvements: the PV-PCM configuration achieved a 68.04% increase in power generation, while the PV-PCM-TEG and PV-TEG-PCM setups recorded efficiency gains of 43.06% and 37.51%, respectively. Efficiency gains relative to the standalone PV system were 33.33% for PV-PCM, 25.76% for PV-PCM-TEG, and 21.21% for PV-TEG-PCM. The results demonstrate that integrating TEG and PCM technologies significantly enhances solar PV performance and offers promising solutions for optimizing solar energy systems in real-world conditions.

Abstract: The usage of adhesively bonded lap joints in industrial applications has been growing in recent years because of the numerous advantages compared to other joining processes such as fastening, welding, and riveting. For effective design of the adhesively bonded engineering lap joints, it is essential to govern the failure potential of a particular adhesive joint under a certain load causing some stress and strain. In this work, study has been carried out by the application of multiple adhesives along the bondline region of lap joint. The objective of this paper is to experimentally examine the results of applications of single and multi-adhesives material with very different mechanical behavior along the bondline region in the single lap adhesive joint. Experimental investigations have been carried out for extracting load displacement data using tensile testing machine, Tensometer, having a capacity of 2 tonne. Multi Adhesive joint can minimize the stress concentration and improve joint strength by using different adhesive stiffness along the bondline region of lap joint and the outcome shows computable increase in the strength of the multiple adhesive bonded lap joints associated with those in which single adhesives were used over the full length of the bondline region.

Abstract: To our knowledge, very few models have described the thermal behavior of granular media or powders as a function of the mechanical stresses to which they are subjected. In recent years, many researchers have expressed great interest in establishing laws that can show the relationship between the apparent thermal conductivity and the mechanical behavior of granular media. This paper presents an experimental study of heat transfer enhancement using granular blocks. A number of experiments were carried out in the test section of a wind tunnel where velocity and temperature measurements were performed. The velocity profiles permitted us to have an idea on the flow structure in the presence of granular blocks. The temperature measurements under various operating conditions (various Reynolds numbers and granular blocks structures) led us to the conclusion that using granular blocks can improve the thermal transfer in comparison with the case of a smooth channel and this enhancement is strongly dependent on the geometrical and thermo-physical properties of these blocks.

Abstract: The seismic vulnerability and resulting damages to vaulted masonry is continuously observed with each new earthquake. The understanding of these systems is quite strong, and reinforcement strategies and techniques are continually advancing. Unfortunately, the application of reinforcement is typically applied in a way that the failure transforms directly from one of stability to strength. This direct transformation overlooks the potential behaviors of the system that exist between the two limits. To investigate and better understand the intermittent behavior of masonry arches, an in-scale dry joint masonry arch subjected to hinge control and a tilting plane loading condition was experimentally tested. The result of that experimentation revealed that the capacity can be increased and the failure defined, but the non-ideal conditions of slip and base deformations were observed as well. This work presents the second experimental campaign of a full-scale dry stack masonry arch subjected to hinge control and a tilting plane loading condition. In this campaign, the issue of slip is addressed in the arch construction, and the results show that the capacity of the full-scale arch can be increased and the failure defined.

Abstract: With each new earthquake the damages to vaulted masonry and their vulnerability are continuously observed. Understanding the behaviour of these systems continues to increase, and reinforcement strategies and techniques are continually advancing. The application of reinforcement is often done such that the failure of the system is transformed directly from one of stability to strength. This direct transformation overlooks the intermittent stages that exist, and thus provides a partial picture of the system. An experimental campaign was carried out to test the capacity of a dry-stack masonry arch subjected to hinge control and failed through a tilting test. From the experimentation, it was observed that controlling the hinge locations can increase the resistance of the arch while also providing a defined failure mechanism, but the capacity of the system was greatly reduced when compared to numerical results. Investigation into the capacity reduction revealed stable mechanical deformations resulting from a non-rigid reinforced base joint. This work focuses on the relationship between capacity and stable deformations to calculate a rotational stiffness value for the non-rigid reinforced base joint.

Abstract: In this paper an experimental research was performed in case of a human complex motion. The research aim was to evaluate the joint trajectories and angular variations of a human upper limb. Thus an experimental motion analysis was performed, by using a modern equipment called VICON Equipment and the interest joints are: shoulder, elbow and wrist. The experimental activity was developed on a human subject when perform a complex motion from baseball sport. The obtained results will be useful for the temporal recovery of the athletes’ complex motions after a severe injury or to reshape the upper arm behavior when strikes the ball in case of baseball athletes.

Abstract: Nickel-based single crystal superalloys have been widely used in modern aircraft, which is related to its high temperature mechanical strength and creep properties. And the initial cubic γ′ precipitates start to coarsen directionally during high temperature creep, which results in the degradation of the mechanical properties, especially the creep properties. Therefore, it is essential to figure out the mechanism of directional coarsening during the period of high temperature creep. In this article, a broad review of rafting mechanism of nickel-based single crystal superalloys is provided. The major work of this critical review is to introduce several experiments and numerical simulations which are used to analyze the evolution of rafting. For three different numerical simulations, their performance, advantage and disadvantage are discussed in detail. Through methods above, the effect on creep properties is summarized.

Abstract: Ventilated façades are increasingly used for retrofitting of exterior walls but also as a passive strategy in the reduction of heat transfer through the envelope of new buildings. If correctly designed and constructed, ventilated façades can lead to energy savings and increased durability of exterior walls. Nevertheless, the main advantage of these constructive systems is the capacity to reduce heat load on the building during the warm season due to the air that flows inside the cavity. The total heat transported by convection is influenced by the temperature distribution inside the channel and depends on many factors, the most important being the channel thickness and the type of the exterior layer. This work presents an experimental study of the temperature reduction capacity for different channel thicknesses and exterior layer tightness on a real scale wooden ventilated façade wall.

Abstract: Technology of precast reinforced concrete finds its application in construction of buildings as well as transport infrastructure. Placement of a dapped-end beam on a corbel is one of the typical details for this construction technology. Designing of a dapped-end is crucial for the whole beam because any potential crack decreases the overall stiffness of the beam and can cause a collapse of the whole structure in the worst case. This paper presents results of an experimental research which was performed on a set of 6 small-scale dapped-end beams. Two different ways of prestressing were applied to experimental specimens and their ultimate-load bearing capacity were compared with plain concrete samples and with reinforced concrete samples. The results of this work suggest that horizontal prestressing technique is more efficient than vertical prestressing technique if the same prestressing force is applied.