Polish School of Medicine at the University of Edinburgh (1941-1949): a case study in the transnational history of Polish wartime migration to Great Britain

More than 400 Polish medical refugees were associated with the Polish School of Medicine (PSM) at the University of Edinburgh between 1941 and 1949. This dissertation argues that the history of the PSM can fully be understood only as a part of the refugees’ broader experience of impelled or forced migration during and immediately after the Second World War. The key findings of this case study demonstrate that the opportunity to study or work at the PSM enabled the majority of Polish exiles to overcome, to a varying extent, their refugee predicament, while medical qualifications, transferable skills and trans-cultural competency obtained in wartime Britain allowed them to pursue professional and academic careers in different countries of post-war settlement, thus in turn contributing to a global circulation of medical knowledge and practice, especially between the University of Edinburgh and Poland. This specific case study contributes to the existing knowledge of Polish wartime migration to Britain in three interrelated ways. Firstly, an overarching transnational approach is used to combine and transcend Polish and British scholarly perspectives on, respectively, emigration or immigration. Secondly, the conceptual insularity of the existing literature on the topic is challenged by analysing archival, published and digital sources pertaining to the PSM with the help of various theoretical models and concepts borrowed from forced migration and diaspora studies. Thirdly, the conventional historiography of Polish-British wartime relations is challenged by emphasising the genuinely global ramifications of the PSM’s history. By interpreting the history of the PSM with the help of different analytical tools, such as Kunz’s and Johansson’s models of refugee movement and Tweed’s theory of diasporic religion, this dissertation provides a conceptual blueprint for further research on Polish wartime migration to Britain. In turn, this case study contributes to the development of forced migration and diaspora studies not only by empirically testing the explanatory power of existing theoretical models, but also by suggesting possible new conceptual avenues, such as analysing the pre-existing trans-cultural experiences of both Polish medical refugees and their hosts at the University of Edinburgh, and adding to the ‘triadic relationship’ of diaspora, homeland and host society a fourth dimension, i.e. conflict and cooperation between different migrant or refugee communities within the same host society

The Efficient Computational Tools For The Design Process Of The Transcritical Two-Phase Ejectors For Natural-Based Working Fluids

Naturalbased working fluids for refrigeration are becoming a standard commercial solution due to the dynamic research and development in this area as well as law regulations. The stateoftheart ejector technology for R744 systems reached current status due to a significant interest on modelling approaches and effective regulation concepts. The development path of the fast and efficient design tools based on the numerical simulations could be described as a key feature for the R744 commercial technology. In this study, one of the most effective numerical approaches dedicated for the twophase CO2 ejector design and analysis is discussed. Namely, homogeneous equilibrium and relaxation model for high motive pressures and mixture approach for lower motive pressures were reviewed. According to the requirements of the effective design tools, the comparison also included a prediction of the vapour quality at given operating conditions and the corresponding computational costs. Moreover, several research studies on swirling and bypassing solutions as well as commercial applications of multiejector device and reduced order models for regulation systems where aforementioned models were used was described. Conclusions on a potential of the reviewed approaches were formulated having regard possible utilisation for the design process of the ejector based R744 systems

Heat Transfer Process Within The R744 Two-phase Ejector: Numerical And Experimental Study

The proposed three dimensional CFD model to simulate the influence of the heat transfer on the R744 two-phase ejector performance is presented. The numerical model was developed based on the homogeneous real fluid flow assumption with the enthalpy-based formulation of the energy equation. The R744 two-phase ejector was designed to evaluate the temperature profile within the ejector walls. The prototype R744 ejector for experimental investigation was manufactured by Institute of Thermal Technology and ATM in Poland. The performance measurements were carried out at a R744 test facility at SINTEF/NTNU in Norway. The foregoing ejector was equipped with the thirteen thermocouples located inside the ejector to measure the wall temperature in different ejector section i.e. the motive nozzle, the suction nozzle, the mixing section and the diffuser. The experimental test campaign at different operating conditions typical for refrigeration application was carried out and the uncertainty of the measurement was defined. Moreover, the experimental data are applied to validate the CFD results at defined operating conditions. The numerical results were set to evaluate the influence of the wall temperature on the two-phase flow parameters. In addition, the heat transfer coefficient of the two-phase flow within the ejector was estimated. The analysis of the heat transfer process within the R744 two-phase ejector let to investigate the influence of the ambient conditions and the different temperature levels of the motive and suction streams on the ejector performance

Thermal analysis of 8.5 MVA disk-type power transformer cooled by biodegradable ester oil working in ONAN mode by using advanced EMAG–CFD–CFD coupling

Power transformers are the first devices used to transfer the electrical energy produced in power plants to the grid to supply the industrial and individual receivers with electricity. The heat generation in windings and core, being an effect of the power losses, is usually dissipated in large units by using mineral oils, which are harmful to the environment. Nowadays, the industry and global society seek environmentally-friendly alternatives. One of the most promising substitute for their high biodegradability, safety in operation, and favourable thermo-physical properties are natural ester oils. For this reason, a numerical study of 8.5 MVA disk-type power transformer cooled using conventional mineral oil and a commercially used rapeseed ester oil is presented in this paper. Moreover, due to different thermal behaviour of the considered oils, the comparison was made for the unit working in different seasons of hot and moderate climate zones (Argentina and Poland). In the numerical approach, electromagnetic (EMAG) and computational fluid dynamics (CFD) models were used for a detailed study of the selected device. In particular, a novel and very efficient EMAG–CFD–CFD coupling procedure was developed to assess the cooling of the large power transformer. Such a coupled computational procedure allowed for the detailed investigation of the power loss, oil flow characteristics, and temperatures with a satisfying computational effort. The results showed that the average windings temperatures are higher by 2–9 K when the ester oil is used, dependent on the ambient conditions. The hotspot temperature in the low voltage windings increased by up to 9 K and up to 18 K in the high voltage windings using ester oil. According to the results, the oil duct construction requires modification in the high voltage region for transformers cooled using mineral oil in cold climate conditions.Fil: Stebel, Michal. Silesian University Of Technology; PoloniaFil: Kubiczek, Krzysztof. Silesian University Of Technology; PoloniaFil: Rios Rodriguez, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Palacz, Michal. Silesian University Of Technology; PoloniaFil: Garelli, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Melka, Bartlomiej. Silesian University Of Technology; PoloniaFil: Haida, Michal. Silesian University Of Technology; PoloniaFil: Bodys, Jakub. Silesian University Of Technology; PoloniaFil: Nowak, Andrzej J.. Silesian University Of Technology; PoloniaFil: Lasek, Pawel. Silesian University Of Technology; PoloniaFil: Stepien, Mariusz. Silesian University Of Technology; PoloniaFil: Pessolani, Francisco. Tadeo Czerweny S.a.; ArgentinaFil: Amadei, Mauro. Tadeo Czerweny S.a.; ArgentinaFil: Granata, Daniel. Tadeo Czerweny S.a.; ArgentinaFil: Storti, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Smolka, Jacek. Silesian University Of Technology; Poloni

Development of the natural working fluid‐based refrigeration system for domestic scale freeze‐dryer

In this work, the analysis of the refrigeration system designed for the FrostX 10 freeze‐dryer is presented. The main goal of this study was to experimentally investigate the reference R452a freeze‐dryer and prepare recommendations for a machine based on the R290 refrigeration unit. In order to guarantee the temperature requirements and efficient operation of that unit, the analysis of suitable natural refrigerants was performed. Consequently, propane (R290) was selected. In addition, a number of modifications were introduced for the prototype system. System analysis showed that the replacement of the refrigerant in the existing system improves the system energy efficiency by approximately 18%. During the experimental campaign of the basic refrigeration unit, an unstable operation of the evaporator was found. The concept of a new cooling system for a prototype device was presented. The configuration and type of heat exchanger to maximise the performance of the ice trap of the freeze‐dryer were proposed.Development of the natural working fluid‐based refrigeration system for domestic scale freeze‐dryeracceptedVersio

Non-equilibrium approach for the simulation of CO2 expansion in two-phase ejector driven by subcritical motive pressure

A non-equilibrium approach was proposed for highly accurate modelling of the expansion process during two-phase flow in the convergent-divergent motive nozzle of an R744 ejector. Comprehensive mapping of the coefficients used in the source terms of the additional transport equation of the vapour quality was provided on the basis of four ejector geometries. The calibration range contained motive pressures from 50 bar to 70 bar, where the prediction quality of the homogeneous equilibrium (HEM) and relaxation (HRM) models, was unsatisfactory. The calibrated model was validated on the basis of experimental mass flow rate data collected from 150 operating points. The mapping results were utilised for final model derivation in the form of an approximation function for R744 expansion. The validation process resulted in satisfactory relative error below 10% for the vast majority of the cases. Moreover, 70% of the simulated cases were considered with a mass flow rate discrepancy below 7.5% in the inaccuracy. Finally, the selected cases were compared and discussed with the HEM approach on the basis of field results. © 2020 Elsevier Ltd and IIRacceptedVersio

A gas ejector for CO2 supercritical cycles

he CO2 ejectors are recently often used as the main expansion device in the modern refrigeration cycles. On the other hand, according to the newest literature the implementation the ejectors into supercritical CO2 power cycles increase its performance. The recent studies showed that in case of the power cycles the ejector pressure lift and mass entrainment ratio are relatively high. Therefore, the main scope of this paper is the investigation of the possibilities of designing the ejector for supercritical Brayton CO2 system. The CFD based computational tool was used to design the ejector for the considered cycle. The system analysis was used to define the ejector on design point. The results of that analysis showed that the required pressure lift and must be equal to 103 bar and mass entrainment ratio equal to 0.995, respectively. The CFD-based evaluation of the proposed ejector showed that these values are impossible to achieve. Therefore, the modifications of the crucial ejector dimensions was performed to increase its performance. Nevertheless, the maximum possible pressure lift for the proposed ejector was equal to 60 bar The analysis of the gathered results showed that the design of the ejector fulfilling the system requirements may be impossible to achieve. © 2018 Elsevier Ltd. All rights reserved.A gas ejector for CO2 supercritical cyclesacceptedVersio

Modified homogeneous relaxation model for the r744 trans-critical flow in a two-phase ejector

acceptedVersio