No description available.

This thesis documents the modelling of generic Environmental Control System(ECS) of an aircraft in Modelica by utilizing components from free version of theTTECCS (Technical Thermodynamic Environmental Control and Cooling Systems) library. In doing so, components used for developing ECS from the TTECCS library are mathematically verified with theoretical formula in MATLAB. Selected components are investigated with valid input data to initialize the simulation and verify its behaviors with corresponding available data. Hereinafter, the object-oriented modelling method is used to integrate ECS components to develop a functional system. The main function of ECS is to regulate the pressure and temperature inside the cabin to accepted physiology flight safetylevels. Different types of ECS architecture are presented in this document. An ECS developed here is based on the bootstrap system and consists only one cooling unit comprised with the source, pipes, two heat exchanger, compressor, turbine, temper-ature control valve, pressure control valve, and sinks. Dry air(Ideal gas) is used as a medium in the system. Temperature drop along each component corresponds to available A320 cruise flight data in order to calculate the top level parameter and to initialize the components, subsequently an ECS system. Several systematized methods for Object-oriented modelling and system design were studied and steps are extracted accordingly that suits to initiate the procedurefor this project, which is also presented. Time domain simulation is performed inModelica and Dymola. A simplified control system is built to regulate the system, therefore restrained it as a future work to develop real in-flight condition control system of an ECS.Top level parameters were selected within valid customized ranges for developing a performance map of the components. After generating the map, optimal data from the map were taken to initialize final ECS. The simulation results of the final model is then compared to A320 flight data which is comparable in behavior; this was expected. Above all, simulation environment Modelica and free version of TTECCS library components are reliable to develop ECS in order to investigate ECS components behavior and predict cabin conditions before developing a prototype.

The cabin environment of a commercial aircraft, including cabin layout and the quality of air supply, is crucial to the airline operators. These aspects directly affect the passengers’ experience and willing to travel. This aim of this thesis is to design the cabin layout for flying wing aircraft as part of cabin environment work, followed by the air quality work, which is to understand what effect the ECS can have in terms of cabin air contamination. The project, initially, focuses on the cabin layout, including passenger cabin configuration, seat arrangement and its own size due to the top requirements, of a conventional aircraft and further into that of a flying wing aircraft. The cabin work in respect of aircraft conceptual design is discussed and conducted by comparing different design approaches. Before the evaluation of cabin air quality, an overall examination of the main ECS components involved in the contaminants access will be carried on and, therefore, attempt to discover how these components influence the property of the concerned contaminants. By case study in the B767 ECS, there are some comments and discussions regarding the relationship between the cabin air contaminations and the passing by ambient environment. The thesis ends up with a conclusion explaining whether or not the contaminated air enters the occupants’ compartments on aircraft and proposing some approaches and engineering solutions to the continue research.

Nowadays the aviation industry is playing an important role in our daily life, since is the main medium that satisfies the present human needs to reach long distances in the fastest way. But such benefit doesn’t come free of collateral consequences. It is estimated that each year, only the air transport industry produces 628 mega tonnes of CO2. Therefore, urgently actions need to be implemented considering that the current commercial fleet will be doubled by 2050. The research field for more efficient aircraft systems is a very constructive field; where novel ideas can be exploited towards the mitigation of the coming air transport development. In this research the configuration of the Environmental Control System (ECS) has been analysed aiming to reduce its energy consumption for both, fixed-wing and rotary-wing aircraft. This goal is expected to be achieved mainly through the replacement of the main source of power that supplies the ECS, from pneumatic to electric. Differently from the conventional ECS, a new electric-source technology is integrated in the system configuration to compare its effects on the energy consumption. This new technology doesn’t bleed air directly from the engines; instead of that, it takes the air directly from the atmosphere through the implementation of an electric compressor. This new technology has been implemented by Boeing in one of its most recent airplanes, the B787. Towards achieving the main goal, a framework integrated with five steps has been designed. An algorithmic analysis is integrated on the framework. The first step meets the required aircraft characteristics for the analysis. The second step is in charge of meeting the mission profile characteristics where the overall analysis will be carried out. The third step assesses the conventional ECS penalties. The fourth step carries out a complex analysis for the proposed electric ECS model, from its design up to its penalties assessment. The fifth step compares the analysis results for both, the conventional and the electric models. The fourth step of the framework, which analyses the electric ECS, is considered the most critic one; therefore is divided in three main tasks. Firstly, a small parametric study is done to select an optimum configuration. This task is carried out towards meeting the ECS air conditioning requirements of a selected aircraft. Secondly, the cabin temperature and pressurization are simulated to analyse the response of the configured electric ECS for a mission profile. And finally, the fuel penalties are assessed in terms of system weight, drag and fuel due power-off take. To achieve the framework results, a model which receives the name ELENA has been created using the tool Simulink®. This model contains 5 interconnected modules; each one reads a series of inputs to perform calculations and exchange information with other modules.

The present thesis deals with the analysis of Environmental Control System (ECS) as a part of the aircraft conceptual design. The research focuses on developing methods for modelling, simulation and optimization of current and future cooling technologies suitable for aircraft applications. The work started with a pre-study in order to establish the suitability of different cooling technologies for ECS application. Therefore, five technologies namely, Bootstrap (BS), Reverse-Bootstrap (RBS), vapour cycle system (VCS), magnetic cooling (MC) and thermo-electric cooling (EC), were assessed from a theoretical point of view by the method of benchmarking. This resulted into the selection of three most suitable technologies that were further modelled and simulated in Dymola. In order to compare the optimum designs for each technology, the models were optimized using the modeFRONTIER software. The comparison was performed based on the optimum ratio of maximum power of cooling and minimum fuel penalty. The results showed that VCS has the “best” performances compared to BS and RBS. In addition to the active technologies, passive cooling methods such as liquid cooling by means of jet-fuel and poly-alpha-olefin were considered to address high heat transfer rates. In order to apply the cooling technologies in the ECS, concept system architectures were formulated using the functional analysis. This led to the identification of basic functions, components and sub-systems interaction. Based on the comparison carried out previously and the functional analysis, two ECS architectures were developed. Design optimization procedure was applied further in order to assess each concept and also to study the differences between the two concept architectures. The results depict the complex interaction of different key parameters of the architectures and their influence on the outcome. The study culminated with a proposed methodology for formulation of systems architecture using information from the optimization results and a robust functional analysis method. To sum up, the thesis proposes a simulation-based optimization method that allows inclusion of ECS system in aircraft conceptual design phase. The study also proves the complexity of the conceptual design stage for ECS architectures which highly influences the design of the combat aircraft.

No description available.

The modern military aircraft can be defined as a System of Systems (SoS); several distinct systems operating simultaneously across boundary interfaces. As the on-board subsystems have become more complex and diverse, the development process has become more isolated. When considering thermal management of distributed heat loads, the aircraft has become a collection of individually optimised components and subsystems, rather than the implementation of a single system to perform a given task. Avionic thermal management is quickly becoming a limiting factor of aircraft performance, reliability and effectiveness. The challenge of avionic thermal management is growing with the increasing complexity and power density of avionic packages. The aircraft relies on a heat rejection growth capacity to accommodate the additional through-life avionic heat loads. Growth capacity is defined as an allowable thermal loading growth designed into the system by the underutilisation of spatial and cooling supply at aircraft introduction; however, this is a limited resource and aircraft subsystem cooling capability is reaching a critical point. The depleted growth capacity coupled with increased avionic power demands has led to component thermal failure. However, due to the poor resolution of existing data acquisition, experimental facilities or thermodynamic modeling, the exact inflight-operating conditions remain relatively unknown. The knowledge gap identified in this work is the lack of definitive methodology to generate high fidelity data of in-flight thermal conditions of fast-jet subsystems and provide evidence towards effective future thermal management technologies. It is shown that, through the development of a new methodology, the knowledge gap can be reduced and as an output of this approach the unknown system behaviour can be defined. A multidisciplinary approach to the replication, analysis and optimisation of a fast-jet TMS is detailed. The development of a new Ground Test Facility (GTF) allows previously unidentified system thermal behaviour to be evaluated at component, subsystem and system level. The development of new data to characterise current thermal performance of a fast jet TMS allows recommendations of several new technologies to be implemented through a component led integrative system optimisation. This approach is to consider the TMS as a single system to achieve a single goal of component thermal management. Three technologies are implemented to optimise avionic conditions through the minimisation of bleed air consumption, improve avionic reliability through increased avionic component isothermalisation and increase growth capacity through improved avionic heat exchanger fin utilisation. These component level technologies improved system level performance. A reduction in TMS bleed air consumption from 1225kg to 510kg was found to complete a typical flight profile. A peak predicted aircraft specific fuel consumption saving of 1.23% is seen at a cruise flight condition because of this approach to avionic thermal management.

The thesis deals with design and optimization of environment in cabins of small transport aircrafts, especially in terms of thermal comfort and quality of ventilation. The design of air distribution systems and structural design were optimized and most important parts of cabin design with highest impact on the quality of thermal comfort and ventilation were identified based on literature research and experience of the author. The chosen modifications and their influence on the microclimate inside the cabin were investigated using the CFD model, which was validated by results obtained from measurements of flow and temperature fields in the cabin mock-up of small transport aircraft EV-55. Next optimizations were investigated: The type of air distribution system, The geometry of ducts of air distribution system, Thickness of thermal insulation and Emissivity of internal surfaces. Thermal comfort was assessed based on the methodology of the equivalent temperature and comfort zones diagram developed by H. O. Nilsson and for assessing the quality of ventilation the concept of based on index of the age of the air was used. Fifty cases were simulated in total and base of its results Modified mixing ventilation with original air ducts geometry have been evaluated as an optimum. The ducts geometry of Modified mixing ventilation system was suggested by author specially for the thesis. In combination with high thermal insulation of walls and high emissivity of the interior, then this system of ventilation ensures maximum thermal comfort and quality of ventilation for the investigated range of environmental and operational conditions.