No description available.

Liquid-metal Rankine power conversion systems (PCS) coupled with a fission reactor remain an attractive option for space power applications because system specific power and efficiency is very favorable for plant designs of 100 kW(e) or higher. Potential drawbacks to the technology in a reduced gravity environment include two-phase fluid management processes such as liquid-vapor phase separation. The most critical location for phase separation is at the boiler exit where only vapor must be sent to the turbine because blade erosion occurs from high velocity liquid droplets entrained by vapor flow. Previous studies have proposed that rotary separators be used to separate the liquid and vapor from a two phase mixture. However these devices have complex turbo machinery, require kilowatts of power and are untested for high vapor flow conditions. The Interphase Transport Phenomena (ITP) laboratory has developed a low-power, passive microgravity vortex phase separator (MVS) which has already proven to be an essential component of two-phase systems operating in low gravity environments. This thesis presents results from flight experiments where a Rankine cycle was operated in a reduced gravity environment for the first time by utilizing the MVS for liquid and vapor phase separation. The MVS was able to operate under saturated conditions and adjust to system transients as it would in the Rankine cycle by controlling the amount of liquid and vapor within the device. A new model is developed for the MVS to predict separation performance at high vapor flow conditions for sizing the separator at the boiler, condenser, and turbine locations within the cycle by using a volume limiting method. This model factors in the following separator characteristics: mass, pumping power, and available buffer volume for system transients. The study is concluded with overall Rankine efficiency and performance changes due to adding vortex phase separation and a schematic of the Rankine cycle with the integration of the MVS is presented. The results from this thesis indicate the thermal to electric efficiency and specific mass of the cycle can be improved by using the MVS to separate the two phases instead of a rotary separator.

Liquid-metal Rankine power conversion systems (PCS) coupled with a fission reactor remain an attractive option for space power applications because system specific power and efficiency is very favorable for plant designs of 100 kW(e) or higher. Potential drawbacks to the technology in a reduced gravity environment include two-phase fluid management processes such as liquid-vapor phase separation. The most critical location for phase separation is at the boiler exit where only vapor must be sent to the turbine because blade erosion occurs from high velocity liquid droplets entrained by vapor flow. Previous studies have proposed that rotary separators be used to separate the liquid and vapor from a two phase mixture. However these devices have complex turbo machinery, require kilowatts of power and are untested for high vapor flow conditions. The Interphase Transport Phenomena (ITP) laboratory has developed a low-power, passive microgravity vortex phase separator (MVS) which has already proven to be an essential component of two-phase systems operating in low gravity environments. This thesis presents results from flight experiments where a Rankine cycle was operated in a reduced gravity environment for the first time by utilizing the MVS for liquid and vapor phase separation. The MVS was able to operate under saturated conditions and adjust to system transients as it would in the Rankine cycle by controlling the amount of liquid and vapor within the device. A new model is developed for the MVS to predict separation performance at high vapor flow conditions for sizing the separator at the boiler, condenser, and turbine locations within the cycle by using a volume limiting method. This model factors in the following separator characteristics: mass, pumping power, and available buffer volume for system transients. The study is concluded with overall Rankine efficiency and performance changes due to adding vortex phase separation and a schematic of the Rankine cycle with the integration of the MVS is presented. The results from this thesis indicate the thermal to electric efficiency and specific mass of the cycle can be improved by using the MVS to separate the two phases instead of a rotary separator.

No description available.

Gas turbine engines are conceptually designed using performance maps that describe the compressor’s effect on the cycle. During the traditional design process, the cycle designer selects a compressor design point based on criteria to meet cycle design point requirements, and performance maps are found or created for off-design analysis that meet this design point selection. Although the maps always have a pedigree to an existing compressor design, oftentimes these maps are scaled to account for design or technology changes. Scaling practices disconnect the maps from the geometry and flow associated with the reference compressor, or the design parameters which are needed for compressor preliminary design. A goal in gas turbine engine research is to bridge this disconnect in order to produce acceptable performance maps that are coupled with compressor design parameters. A new compressor conceptual design and performance prediction method has been developed which will couple performance maps to conceptual design parameters. This method will adapt and combine the key elements of compressor conceptual design with multiple-meanline analysis, allowing for a map of optimal performance that is attached to reasonable design parameters to be defined for cycle design. This method is prompted by the development of multi-fidelity (zooming) analysis capabilities, which allow compressor analysis to be incorporated into cycle analysis. Integrating compressor conceptual design and map generation into cycle analysis will allow for more realistic decisions to be made sooner, which will reduce the time and cost used for design iterations.

This thesis develops a paradigm for conceptual design based on the idea that dimensional analysis can improve the evaluation and comparison of concepts of solution during the conceptual design process. The conceptual design approach developed in this research is a combination of tasks which starts with the identification of the customer needs in a formalized manner is followed by the generation of design concepts taking into account the different phases of the physical life cycle and ends by the evaluation and adequacy analysis of the concepts of solution with the formalized needs.<br /><br />The General Design Theory (GDT) is used as the methodological basis of this work. Using the results of GDT, the research introduces a definition of the concept of function which is generic and not dedicated to a solution-based approach. Consequently the concept of function fulfils its intended objective of modelling the design problems at a general level. In addition to the concept of function, this thesis introduces a series of classifications based on generic concepts and rules aimed at generating concepts of solutions progressively. All these concepts are integrated into the developed metamodel framework. The metamodel provides a group of generic concepts associated with laws and mapped with a normalized functional vocabulary. The metamodel framework is an intermediate structure developed in order to provide guidance during the synthesis process and to meet the initial condition in order to transform the classification structure into a metric space. A metric space is a topological space with a unique metric. The transformation of the initial topological space into a metric space can be obtained when a series of conditions are verified. The first condition consists of clustering the concepts of solutions in order to underline the comparable aspects in each of them. This is done by using a set of dedicated rules. In addition three other fundamental conditions should be obtained. The metamodel framework ensures the first condition; an enhanced fundamental system of unit provides the second condition and a paradigm of separation of concept the third one. When all these three conditions are verified, it becomes possible to transform the design problems modelled by four types of generic variables into a series of dimensionless groups. This transformation process is achieved by using the Vashy-Buckingham theorem and the Butterfield's paradigm. The Butterfield's paradigm is used in order to select the minimum set of repeated variables which ensure the non-singularity of the metrization procedure. This transformation process ends with the creation of a machinery dedicated to the qualitative simulation of the concepts of solutions. The thesis ends with the study of practical cases.

This thesis addresses the need for an optimization method which can simultaneously optimize and balance an aerothermodynamic cycle. The method developed is be able to control cycle design variables at all operating conditions to meet the performance requirements while controlling any additional variables which may be used to optimize the cycle and maintaining all operating limits and engine constraints. The additional variables represent degrees of freedom above what is needed for conservation of mass and energy in the engine system. The motivation for such a method is derived from variable cycle engines, however it is general enough to use with most engine architectures. The method is similar to many optimization algorithms but differs in its implementation to an aircraft engine by combining the cycle balance and optimization using a Newton-Raphson cycle solver to efficiently find cycle designs for a wide range of engine architectures with extra degrees of freedom not needed to balance the cycle. Combination of the optimization with the cycle solver greatly speeds up the design and optimization process. A detailed process description for implementation of the method is provided as well as a proof of concept using several analytical test functions. Finally, the method is demonstrated on a separate flow turbofan model. Limitations and applications of the method are further explored including application to a multi-design point methodology.

Interest in environmental issues has increased enormouslyover the last few decades and environmental problems areperceived to be on the increase. Due to the fact that thenumber of products on the market increases enormously, it isevident that we face a great challenge to overcome the problemconcerning our consumer society. An increasing barrage oflegislation accompanied by the public’s awareness of, andconcern for, the environment forcing the industry to respond.Products and their environmental impact have moved to thecentre stage and it is widely believed that designers have akey role in adapting products to a sustainable society. Threekey issues are identified in this development scenario: (a) theimportance of adapting products to a more sustainable society,(b) the specific situation facing the designer, especially inearly design phases, and (c) balancing environmental impactswith functional preferences. Research in this thesis presents a theoretical framework fordescribing environmental issues and the role of the designer inproduct development, as well as functional characteristics ofproducts in the early phases of design. Based on anengineering-design science foundation, theoretical models andconcepts have been developed describing how both functional andenvironmental preferences can be visualised in design forenvironment and product development. Case studies andinterviews have been performed and integrated into a coherenttheoretical model for identifying and evaluating functional andenvironmental preferences within ecodesign approach andreasoning. The overall concept proposed in this thesis is called theeco functional matrix, based on two parts: functional profileand environmental profile. The functional profile represent thefunctional characteristics and environmental profile theenvironmental characteristics respectively of a product in theearly phases of design. One of the objectives behind theconcept is to highlight the importance of balancing functionalrequirements and environmental impacts, presenting both theadvantages and disadvantages of the product. The basic idea isto account for user and societal preferences as well asenvironmental impact when assessing alternative productconcepts at early design stages. Balancing both the functionalrequirements and the negative environmental impacts of productsis the road to sustainable development. <b>KEYWORDS</b>Design for environment, life-cycle design,eco-design, eco-design methods, product environmentalcharacteristics, product functional characteristics, customerbenefit, value analysis, functional profile, environmentalprofile, eco functional matrix, product properties.

<p>Interest in environmental issues has increased enormouslyover the last few decades and environmental problems areperceived to be on the increase. Due to the fact that thenumber of products on the market increases enormously, it isevident that we face a great challenge to overcome the problemconcerning our consumer society. An increasing barrage oflegislation accompanied by the public’s awareness of, andconcern for, the environment forcing the industry to respond.Products and their environmental impact have moved to thecentre stage and it is widely believed that designers have akey role in adapting products to a sustainable society. Threekey issues are identified in this development scenario: (a) theimportance of adapting products to a more sustainable society,(b) the specific situation facing the designer, especially inearly design phases, and (c) balancing environmental impactswith functional preferences.</p><p>Research in this thesis presents a theoretical framework fordescribing environmental issues and the role of the designer inproduct development, as well as functional characteristics ofproducts in the early phases of design. Based on anengineering-design science foundation, theoretical models andconcepts have been developed describing how both functional andenvironmental preferences can be visualised in design forenvironment and product development. Case studies andinterviews have been performed and integrated into a coherenttheoretical model for identifying and evaluating functional andenvironmental preferences within ecodesign approach andreasoning.</p><p>The overall concept proposed in this thesis is called theeco functional matrix, based on two parts: functional profileand environmental profile. The functional profile represent thefunctional characteristics and environmental profile theenvironmental characteristics respectively of a product in theearly phases of design. One of the objectives behind theconcept is to highlight the importance of balancing functionalrequirements and environmental impacts, presenting both theadvantages and disadvantages of the product. The basic idea isto account for user and societal preferences as well asenvironmental impact when assessing alternative productconcepts at early design stages. Balancing both the functionalrequirements and the negative environmental impacts of productsis the road to sustainable development.</p><p><b>KEYWORDS</b>Design for environment, life-cycle design,eco-design, eco-design methods, product environmentalcharacteristics, product functional characteristics, customerbenefit, value analysis, functional profile, environmentalprofile, eco functional matrix, product properties.</p>

The Linear Economy cannot any longer be sustained by the eco-system: virgin resources are limited and destined to terminate soon if the contemporary production and consumption model will be maintained. For this reason, in the last few years Circular Economy has become an increasingly discussed topic worldwide. Through the adoption of strategies that close-the-loop of the traditional linear production system, Circular Economy aims to find solutions that can create a balance between economy, society and environment. This study aims to provide a holistic overview on the main theories and strategies that can ease a business transition to a Circular Economy model, to analyse challenges and opportunities connected to this conversion and to present a concrete tool developed for this purpose. The Life Cycle Design theory is here discussed and contextualised within the furniture industry reality since this study has been executed in collaboration with IKEA, the company case study of this thesis. An academic and professional literature review have been performed in order to gather information about theory and practice related to the implementation of strategies needed by a Circular Economy: product disassembly, recovery, reuse, refurbish, recycle and remanufacturing. The professional literature reviewed point out that the implementation of a circular model can lead to economic advantages and growth’s opportunities for manufacturers in various economic sectors. The implementation of Circular Economy in the furniture industry seems to be in its early stages and it mainly focus, with few exception, on recycling rather than on the more effective reuse, refurbish or remanufacturing operations. This study points out the two main issues that the furniture manufacturers need to solve in order to enable the implementation of more effective circular strategies: product disassembly and recovery. Furthermore, the need of an innovative and holistic approach is discussed with particular emphasis on the importance of a systemic thinking that enable organisation to create their own identity and objectives in relation to the Circular Economy model. The importance of a system that connects and coordinate the sustainable efforts and aims for new products and services is therefore highlighted, suggested and deeply considered in the development of the tool proposed. To conclude, a comparison between two IKEA products (the sofas Söderhamn and Knopparp) was performed to identify the role of the products’ design and development in relation with the implementation of a Circular Economy model. The products were briefly technically analysed and then a comparison between a linear and a circular end-of-life cycle scenario has been represented.