Browsing by Author "Anselmi Palma, Eduardo"

Now showing 1 - 13 of 13
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    A submersible power station: Part A helium power conversion unit
    (MDPI, 2024-11-19) Serna, Jon; Anselmi Palma, Eduardo; Romero, Stefania; Fouflias, Dimitrios; Pilidis, Pericles
    Nuclear power continues to hold great promise in the green revolution, however public opinion regarding its deployment is mixed. A submersible nuclear power station concept is presented here that is expected to allay many concerns that are holding back the growth of nuclear power. This submersible can move under its own power during emergencies and routine maintenance. Being stationed at sea it is earthquake proof. In the case of a tsunami it could decouple from the coast and sail to a location several miles to deeper waters in less than 30 min. Furthermore, it could be built, commissioned, maintained, refueled and scrapped in a country like the UK. This makes it proliferation-proof, a key concern with the wider deployment of nuclear power. In the present evaluation the philosophy and the electric power generation capability of the submersible power station are investigated. This includes a pre-feasibility visualization of the design. An evaluation is carried out into fitting it in a submersible of a size similar to the largest existing nuclear submarines. These designs may enable it to deliver 0.6 to 1 GW of electrical power.
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    Design and optimization of a Tesla pump for ORC applications
    (Technical University of Munich, 2021-10-11) Anselmi Palma, Eduardo; Fiaschi, Daniele; Nicotra, Giovanni; Talluri, Lorenzo
    The Tesla pump is bladeless turbomachinery known for being more resistant to work with hard-to-pump fluids than conventional turbomachinery, thanks to its simple, robust mechanical design and its working principle (viscous forces). A 2D numerical model is developed and a design procedure of a Tesla pump working with several working fluids (water, R1233zd(E), R1234yf) is proposed. A complete design methodology is developed by evaluating the losses of each component and by introducing a rotor model. The main optimizing parameters of the pump are highlighted and assessed and validation of the model with available experimental results is carried out. A design procedure for a Tesla pump prototype is showed and its characteristic curves are obtained and discussed. The results achieved are similar to other experimental Tesla pumps, with a maximum achieved efficiency of 26.8%. The extension of the model to organic working fluids allowed to predict pump efficiencies higher than 50% for low mass flow rate conditions for both assessed fluids.
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    Development of an experimental S-CO2 loop for bottoming cycle applications
    (Unknown, 2016-10-11) Anselmi Palma, Eduardo; Zachos, Pavlos; Collins, Robert; Hassan, Mark
    This paper describes the design of a supercritical carbon dioxide [S-CO2] rig for bottoming power cycle applications. The final envisaged layout of the facility includes a fully coupled compressor-turbine system, a number of heat exchangers to enable heat management of the cycle and a control system for start-ups, shut-downs, inventory control and transient operation of the loop. The objective of the preliminary design phase is to experimentally de-risk the robustness of the closed loop system as well as prove the purpose of individual components and various measurement and control modules.
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    Effect of mixing Mach number and mixing efficiency on the preliminary cycle design of mixed high-BPR turbofans
    (Elsevier, 2019-03-02) Cleton, Bjorn; Anselmi Palma, Eduardo; Pellegrini, Alvise; Pachidis, Vassilios; Laskaridis, Panagiotis
    This article presents the implementation of an updated analytical flow mixing model in a state-of-the-art, non-dimensional gas turbine cycle performance simulation and optimisation tool. The model considers three separate streams in the mixer, each expanding through its own ‘virtual’ nozzle. The use of three streams, compared to one single stream, allows for a more realistic simulation of a mixed exhaust gas turbine. This approach is used in a parametric study to assess the effect of the choice of mixing efficiency and mixer inlet Mach number on the preliminary design of mixed-exhaust, high-bypass ratio turbofan engines. It was found that in terms of best thermal performance, a trade-off exists between mixer inlet Mach number and mixer effectiveness. The findings of this research establish some useful guidelines for the accurate selection of these two parameters to achieve robust cycle designs.
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    Engine strip and build lab: a practical approach to learning gas turbine engines
    (Cambridge University Press (CUP), 2025-01) Anselmi Palma, Eduardo; Kissoon, Sajal; Hann, Gary; Pilidis, Pericles; Pachidis, Vassilios
    The world is currently undergoing a technological transformation with numerous innovative concepts emerging. This shift is driven by remarkable advancements in artificial intelligence and the urgent need for decarbonisation. With this comes a growing demand for skilled engineers who can actively contribute at any stage within the life cycle of a product. This can be the generation of new concepts at low Technology Readiness Levels or contributing actively to their development and operational safety. This paper explores the integration of a 1-day practical activity to reinforce theoretical concepts learned within a classroom-based environment. Small groups of students were given the opportunity of engaging with a small helicopter engine (Rolls-Royce Gnome engine) through the disassembly and reassembly of the exhaust and power turbine section while following the manufacturer’s manual and ensuring industrial norms for safe practice. This hands-on activity included an introduction to tooling, a Gnome familiarisation activity, and an introduction to inspection techniques. Based on the feedback recorded, the students experienced a notable improvement in their basic understanding by effectively reinforcing knowledge acquired within the classroom through active engagement with an actual gas turbine engine.
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    Flow field explorations in a boundary layer pump rotor for improving 1D design codes
    (MDPI, 2023-02-03) Freschi, Rosa; Bakogianni, Agapi; Rajendran, David John; Anselmi Palma, Eduardo; Talluri, Lorenzo; Roumeliotis, Ioannis
    Boundary layer pumps, although attractive due to their compactness, robustness and multi-fluid and phase-handling capability, have been reported to have low experimental efficiencies despite optimistic predictions from analytical models. A lower-order flow-physics-based analytical model that can be used as a 1D design code for sizing and predicting pump performance is described. The rotor component is modelled by means of the Navier–Stokes equations as simplified using velocity profiles in the inter-disk gap, while the volute is modelled using kinetic-energy-based coefficients inspired by centrifugal pumps. The code can predict the rotor outlet and overall pump pressure ratio with an around 3% and 10% average error, respectively, compared to the reference experimental data for a water pump. Moreover, 3D RANS flow-field explorations of the rotor are carried out for different inter-disk gaps to provide insights concerning the improvement of the 1D design code for the better prediction of the overall pump performance. Improvements in volute loss modelling through the inclusion of realistic flow properties at the rotor outlet rather than the detailed resolution of the velocity profiles within the rotor are suggested as guidelines for improved predictions. Such improved design codes could close the gap between predictions and experimental values, thereby paving the way for the appropriate sizing of boundary layer pumps for several applications, including aircraft thermal management.
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    Insights into the flow field and performance of a boundary layer pump
    (American Society of Mechanical Engineers, 2023-10-19) Rajendran, David John; Palaveev, Kyril; Anselmi Palma, Eduardo; Santhanakrishnan, Mani; Pachidis, Vassilios
    A flow field analysis of a realistic, integrated, multi-disc boundary layer pump as is necessary for investigating the reasons for typically quoted low efficiencies in such pumps is described. The study focuses on the 3D RANS solutions of a water boundary layer pump model created to replicate a design which consists of 170 discs and a volute channel. A baseline study is performed to investigate the rotor-only and volute-only flow fields and identify the losses in each as separate systems. Thereafter, an integrated model is characterized for different operating conditions. The flow fields of all three models are discussed and the results of the integrated model are compared to the experimental data. The results from the rotor-only model confirm the typically made claim that the rotor efficiency is relatively high, which in this case is 87% at the design point. The volute on its own indicated a hydraulic efficiency of ~97%. However, the integrated model yielded a rotor efficiency of ~74% and an overall pump efficiency of 51% at the design point, clearly outlining the fact that the effect of the volute integrated with the rotor is the reason for both the rotor and pump efficiency degradation. The reason for this drop in efficiency is discussed by highlighting the change in the flow topologies. The insights into the flow field and the identification of the reason for inefficiencies using a separated component analysis approach provides directions for avenues in which design improvements need to be attempted.
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    Mechanical design and manufacture of a boundary layer pump
    (EDP Sciences, 2023-08-25) Bufalari, Lapo; Anselmi Palma, Eduardo; Rinchi, Mirko; Howard, Kevin; Talluri, Lorenzo; Fiaschi, Daniele
    This paper describes the current efforts to develop and manufacture a first prototype for a boundary layer pump as a mean to assess future and more complex designs. Following an approach of “learning by doing”, a previous design was re-assessed from a mechanical/workshop point of view. Budget constraints and in-house manufacturing capabilities were taken into consideration to deliver a new design, suitable for quick production. Challenges such as disc holding, gap spacing, pump intake, discharge nozzles, and tolerances were addressed. Structural analysis has been conducted; where every single component has been modelled and sized accordingly to standard practices. As a support of structural analysis, FEM analysis was also performed with the aim of identifying, discussing, and fixing any potentially critical issues, particularly regarding the bolts holding together the discs into the power shaft. Finally, modal analysis was performed in order to test the dynamic response of the rotor: its critical frequencies would be far from the working range of the machine. This paper gives an overview of the critical issues to be taken into account during the mechanical design of boundary layer pump prototypes for different working fluids in the field of power generation and thermal management.
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    Multidisciplinary design and manufacturing of a Tesla pump prototype
    (Elsevier, 2024-07-29) Bakogianni, Agapi; Anselmi Palma, Eduardo; Rajendran, David John; Bufalari, L.; Talluri, L.; Ungar, P.; Fiaschi, Daniele
    To widen the range of hydraulic efficiencies of boundary layer pumps, a full design methodology has been proposed in order to identify critical issues for their performance and manufacturing. The methodology integrated a 2D numerical code, CFD and FEM analyses, coupled with manufacturing assessments as feedback mechanism. Considering budget constraints and in-house machining capabilities, a quick first prototype was produced. Analyses of the design are pointing out that the volute design initially chosen will not help to achieve an increase in the overall efficiency. The curves of head achieved with 2D and CFD are in agreement, but the latter determines the losses with larger accuracy, thus achieving lower values of head. The 2D model shows limits in the determination of the efficiency, effectively corrected by the CFD analysis. Critical parameters as disc thickness and gap between discs will require a more sophisticated assembly process and materials outsource. The proposed methodology could be used as a reference for the design and performance evaluation of this kind of turbomachinery in the future. The procedure lead to a prototype design, whose optimal efficiency slightly lower than 30 % was achieved at 5000 rpm with 0.3 mm disks gap.
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    An overview of the Rolls-Royce sCO2-test rig project at Cranfield University
    (Southwest Research Institute, 2018-04-08) Anselmi Palma, Eduardo; Bunce, Ian; Pachidis, Vassilios; Zachos, Pavlos; Johnston, Michael
    An experimental facility is currently under development at Cranfield University, aiming to explore supercritical carbon dioxide as a working fluid for future bottoming power cycle applications for Rolls- Royce. The initial objectives of this experimental program are to de-risk and demonstrate the robustness of a closed loop system, as well as to prove the function and performance of individual components and various measurement and control modules. This paper describes the planning and development phases of the test facility and summarises the lessons learnt from the component specification and component interface processes.
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    Parametric evaluation of S-CO2 Brayton cycles for bottoming applications
    (2016-10-11) Brighenti, Giovanni; Anselmi Palma, Eduardo; Zachos, Pavlos
    Parametric design studies for the preliminary assessment of physical footprint of Supercritical CO2 power plants are presented herein. The aim of the study is to quantify trade-offs between cycle efficiency and plant complexity for a range of S-CO2 cycle configurations.
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    Performance comparison of temperature sensors for closed cycles operating with supercritical CO2
    (Unclear, 2023-03-16) Belleoud, Pierre; Anselmi Palma, Eduardo; Chetwynd-Chatwin, Jason; Roumeliotis, Ioannis
    Near the critical point of carbon dioxide (CO2), small changes in temperature or pressure can result in large changes in the calculation of its thermodynamic properties, thus the right choice of instrumentation is of importance. This paper addresses the challenges related to CO2 temperature measurement in smalldiameter pipes and assesses different sensors utilizing Cranfield University’s supercritical CO2 test rig capabilities. In order to compare temperature sensor types for supercritical CO2, a test tube has been designed to fit different sizes of temperature probes at the discharge of the transcritical compressors at the sCO2 test rig. Different diameters of thermocouples (0.75 to 4.5 mm), Resistance Temperature Detectors (RTDs) and surface sensors were tested and compared in terms of amplitude and adaptability to sudden temperature changes. Results for different fluid conditions in the supercritical region of CO2 were derived. The use of thermowell is discussed as it can offer a suitable compromise between practicality and ‘internal’ measurements. The results presented in this paper aim to provide a comparison of temperature sensors’ performances for different regimes, transient or steady state.
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    Update of the sCO2-test rig at Cranfield University
    (American Society of Mechanical Engineers, 2022-10-28) Anselmi Palma, Eduardo; Belleoud, Pierre; Roumeliotis, Ioannis; Pachidis, Vassilios
    Since 2018, there is an experimental supercritical carbon dioxide (sCO2) facility operating at Cranfield University. The purpose of this rig is to enable the exploration of supercritical carbon dioxide as a working fluid for future bottoming power cycle applications and, more recently, for thermal management applications. The core of the rig is a transcritical closed loop, which has recently been upgraded. The upgrades include an increase in the number of measurement stations, changes to the types of measurements taken, as well as the addition of a new, dedicated data acquisition system. A summary of some of the lessons learned from different test campaigns conducted from 2018 to 2021 is provided, along with a discussion on the measurement upgrades performed. The experience obtained with this rig, as recounted in this paper, could be relevant to similar test rigs or future power cycles applications.