Effects of rotation and buoyancy forces on the flow field behavior inside a triangular rib roughened channel

The flow field inside a triangular cooling channel for the leading edge of a gas turbine blade has been investigated. The efforts were focused on the investigation of the interaction between effects of rotation, of buoyancy forces, and those induced by turbulence promoters, i.e., perpendicular square ribs placed on both leading and trailing sides of the duct. Particle image velocimetry (PIV) and stereo-PIV measurements have been performed for Re-Dh = 10(4), rotation number of 0, 0.2, and 0.6, and buoyancy parameter equal to 0, 0.08, and 0.7. Coriolis secondary flows are detected in the duct cross section, but contrary to the smooth case, they are characterized by a single main vortex and are less affected by an increase of the rotation parameter. Moreover, their main topology is only marginally sensitive to the buoyancy forces. Conversely, the features of the recirculation structure downstream the ribs turned out to be more sensitive to both the buoyancy forces and to the stabilizing/destabilizing effect on the separated shear layer induced by rotation

Rotational effects on the flow field inside a leading edge impingement cooling passage

The work reports for the first time detailed experimental data about the flow field inside an advanced leading edge cooling channel for gas turbine blades. The geometry key features are multiple internal impinging jests and coolant extraction for blade film cooling protection. Measurements have been performed by means of 2D and Stereo PIV, in both static and rotating conditions, with Reynolds number of 30k and 10k and a Rotation number of 0.05, both defined with reference to the jet characteristics. Different crossflow conditions in the feeding channel have been used to simulate the three main blade regions (i.e. HUB, MID, and TIP). The flow inside the feeding channel is significantly affected by rotation, conversely, when moving inside the main impingement duct, the jet core has been found to be only marginal modified due to rotation. Finally, a substantial Reynolds number independence has been found

Rotating heat transfer measurements on a multi-pass internal cooling channel - I rig development

The present contribution is focused on heat transfer measurements on internal cooling channels of a high pressure gas turbine blade in static and rotating conditions. A novel rig designed for the specific purpose was used to assess the heat transfer coefficients on a full internal cooling scheme of an idealized blade. The channel has a multi-pass design. Coolant enters at the blade hub in the leading edge region and move radially outwards inside a two-sided ribbed channel. The second passage is again a two-sided ribbed channel with a trapezoidal cross section of high aspect ratio, while inside the third leg low aspect-ratio cylindrical pin fins are arranged in a staggered configuration to promote flow turbulence. Inside the third passage, the coolant is progressively discharged at the blade trailing edge and finally at the blade tip. The test model differs with respect to the real design only because there is no curvature due to the blade camber. Conversely, the correct stagger angle of the real blade with respect to the rotation axis is preserved. Experiments were performed for static and rotating conditions with engine similar conditions of Re=21000 and Ro=0.074, both defined at the channel inlet. Transient liquid crystal technique was used for the measurement of the heat transfer coefficient (HTC) on both pressure and suction sides internal surfaces of the channel. From the spatially resolved HTC maps available, it is possible to characterize the thermal performances of the whole passage and to highlight the effect of rotation

Rotating heat transfer measurements on a multi-pass internal cooling channel - II experimental tests

The present contribution describes the design and realization of a rotating test rig for heat transfer measurements on internal cooling passages of gas turbine blades. The aim is to study the effects of Coriolis and buoyancy forces on the heat transfer distribution inside realistic cooling schemes. Spatially resolved heat transfer data are obtained by means of transient thermo-chromic liquid crystals (TLC) technique. In order to replicate the same buoyancy effects induced by the Coriolis forces during rotation, the transient measurements are performed with a cold temperature step on the coolant flow. New solutions are adopted to generate the cold temperature step, acquire the experimental data on board of the rotating test model and to control the experimental parameters during tests execution. The main components of the rig will be described in the paper, together with an overview of the data processing methodology that has been developed

Effect of Rotation on a Gas Turbine Blade Internal Cooling System: Experimental Investigation

A detailed aerothermal characterization of an advanced leading edge (LE) cooling system has been performed by means of experimental measurements. Heat transfer coefficient distribution has been evaluated exploiting a steady-state technique using thermochromic liquid crystals (TLCs), while flow field has been investigated by means of particle image velocimetry (PIV). The geometry key features are the multiple impinging jets and the four rows of coolant extraction holes, and their mass flow rate distribution is representative of real engine working conditions. Tests have been performed in both static and rotating conditions, replicating a typical range of jet Reynolds number (Rej), from 10,000 to 40,000, and rotation number (Roj) up to 0.05. Different crossflow conditions (CR) have been used to simulate the three main blade regions (i.e., tip, mid, and hub). The aerothermal field turned out to be rather complex, but a good agreement between heat transfer coefficient and flow field measurement has been found. In particular, jet bending strongly depends on crossflow intensity, while rotation has a weak effect on both jet velocity core and area-averaged Nusselt number. Rotational effects increase for the lower crossflow tests. Heat transfer pattern shape has been found to be substantially Reynolds independen

Geology of the Classical Karst Region (SW Slovenia–NE Italy)

ABSTRACTThe paper aims to present the geology of the western part of the Classical Karst (NW Dinarides), located at the border between Slovenia and Italy. The work is based on archive, published and new data collected by Slovenian and Italian researchers within several scientific national and Cross Border Cooperation projects. The map, produced at a scale of 1:50,000, summarizes the lithological and structural setting and is supplemented by three geological cross-sections of the study area

Biphasic calcium phosphate biomaterials: Stem Cell-derived Osteoinduction or In-vivo Osteoconduction? Novel insights in Maxillary Sinus Augmentation by advanced Imaging

none11noMaxillary sinus augmentation is often necessary prior to implantology procedure, in particular in cases of atrophic posterior maxilla. In this context, bone substitute biomaterials made of biphasic calcium phosphates, produced by three-dimensional additive manufacturing were shown to be highly biocompatible with an efficient osteoconductivity, especially when combined with cell-based tissue engineering. Thus, in the present research, osteoinduction and osteoconduction properties of biphasic calcium-phosphate constructs made by direct rapid prototyping and engineered with ovine-derived amniotic epithelial cells or amniotic fluid cells were evaluated. More in details, this preclinical study was performed using adult sheep targeted to receive scaffold alone (CTR), oAFSMC, or oAEC engineered constructs. The grafted sinuses were explanted at 90 days and a cross-linked experimental approach based on Synchrotron Radiation microCT and histology analysis was performed on the complete set of samples. The study, performed taking into account the distance from native surrounding bone, demonstrated that no significant differences occurred in bone regeneration between oAEC-, oAFMSC-cultured, and Ctr samples and that there was a predominant action of the osteoconduction versus the stem cells osteo-induction. Indeed, it was proven that the newly formed bone amount and distribution decreased from the side of contact scaffold/native bone toward the bulk of the scaffold itself, with almost constant values of morphometric descriptors in volumes more than 1 mm from the border.openGiovanna Iezzi, Antonio Scarano, Luca Valbonetti, Serena Mazzoni, Michele Furlani, Carlo Mangano, Aurelio Muttini, Mario Raspanti, Barbara Barboni, Adriano Piattelli, Alessandra GiulianiIezzi, Giovanna; Scarano, Antonio; Valbonetti, Luca; Mazzoni, Serena; Furlani, Michele; Mangano, Carlo; Muttini, Aurelio; Raspanti, Mario; Barboni, Barbara; Piattelli, Adriano; Giuliani, Alessandr

Designing greenhouse subsystems for a lunar mission: the LOOPS - M Project

The 2020s is a very important decade in the space sector, where international cooperation is moving towards the exploration of the Moon and will lead to stable lunar settlements, which will require new, innovative, and efficient technologies. In this context, the project LOOPS–M (Lunar Operative Outpost for the Production and Storage of Microgreens) was created by students from Sapienza University of Rome with the objective of designing some of the main features of a lunar greenhouse. The project was developed for the IGLUNA 2021 campaign, an interdisciplinary platform coordinated by Space Innovation as part of the ESA Lab@ initiative. The LOOPS-M mission was successfully concluded during the Virtual Field Campaign that took place in July 2021. This project is a follow-up of the V-GELM Project, which took part in IGLUNA 2020 with the realization in Virtual Reality of a Lunar Greenhouse: a simulation of the main operations connected to the cultivation module, the HORT3 , which was already developed by ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development) during the AMADEE-18 mission inside the HORTSPACE project. This paper will briefly describe the main features designed and developed for the lunar greenhouse and their simulation in a VR environment: an autonomous cultivation system able to handle the main cultivation tasks of the previous cultivation system, a bioconversion system that can recycle into new resources the cultivation waste with the use of insects as a biodegradation system, and a shield able of withstanding hypervelocity impacts and the harsh lunar environment. A wide overview of the main challenges faced, and lessons learned by the team to obtain these results, will be given. The first challenge was the initial inexperience that characterized all the team members, being for most the first experience with an activity structured as a space mission, starting with little to no know-how regarding the software and hardware needed for the project, and how to structure documentation and tasks, which was acquired throughout the year. An added difficulty was the nature of LOOPS-M, which included very different objectives that required different fields of expertise, ranging from various engineering sectors to biology and entomology. During the year, the team managed to learn how to handle all these hurdles and the organizational standpoint, working as a group, even if remotely due to the Covid-19 pandemic. Through careful planning, hard work and the help of supervisors, the activity was carried out through reviews, up to the prototyping phase and the test campaign with a successful outcome in each aspect of the project. By the end of the year everyone involved had acquired new knowledge, both practical and theoretical, and learned how to reach out and present their work to sponsors and to the scientific community

Platy limestones. 10 case studies in the Classical Karst

Il progetto RoofOfRock, finanziato nell’ambito del 2° bando di cooperazione transfrontaliera dell’Adriatico IPA 2007-2013 è iniziato nell’ottobre 2012, si concluderà a fine settembre del 2015 e coinvolge 10 partner di 4 nazioni: Slovenia, Italia, Croazia e Bosnia Erzegovina. In qualità di partner associato e stakeholder partecipano le regioni Friuli Venezia Giulia e Veneto. Il progetto RoofOfRock ha tra le sue finalità quelle di proporre un utilizzo del calcare tabulare compatibile con l’ambiente, di favorirne la protezione e la promozione nonché di elaborare delle linee guida utili per una sua valorizzazione come patrimonio naturale e culturale.Pri projektu RoofOfRock, ki je bil izbran za sofinanciranje v okviru 2. poziva Jadranskega čezmejnega programa IPA 2007–2013, sodeluje deset projektnih partnerjev iz štirih držav, in sicer iz Slovenije, Italije, s Hrvaške ter iz Bosne in Hercegovine. Projekt se je začel izvajati oktobra 2012 in se bo zaključil konec septembra 2015. Pri projektu sodelujeta tudi italijanski pokrajini Furlanija - Julijska krajina kot deležnik in Benečija kot pridruženi partner. Namen projekta RoofOfRock je vzpostaviti skupni temelj za trajnostno rabo, zaščito in promocijo ploščastih apnencev ter oblikovati uporabne smernice za trajnostno upravljanje ploščastih apnencev kot skupne naravne in kulturne vrednote na celotnem projektnem prostoru.The RoofOfRock Project is being implemented under 2nd call for ordinary projects of Adriatic IPA CBC Programme 2007, joining 10 partners from 4 countries Slovenia, Italy, Croatia and Bosnia and Herzegovina. It started in October 2012 and is going to be implemented until the end of September 2015. Two Italian Regions Friuli Venezia Giulia and Veneto are participating as stakeholder and associate partner . The RoofOfRock intention is to establish joint platform for platy limestone sustainable use, preservation and promotion, to create the relevant guidelines and to upgrade both individual and joint capacities in preserving such common natural and cultural heritage