The aim of the Diploma Thesis is to discuss the design and construction solution for circulation of the thermodynamic heat pump especially used in the heating industry with stoichiometric combustion of chosen natural gas. The basic components of the proposed heat pump are turbine, compressor and gearbox. To solve the presented aims, the thermodynamic calculation of the individual components, the determination of the efficiency of the whole equipment and the analysis of the physical properties of the natural gas with regard to the specified input and output parameters were considered. In addition, an analysis of the individual components design of the proposed equipment was carried out, on the basis the technically most acceptable variant was chosen and the equipment construction was carried out incl. connecting elements. Drawing documentation is part of the attachments. On the basis of the analysis, it can be stated that the proposed plant leads to energy savings, is ecologically sufficient and has been shown to have approximately twice the amount of heat dissipated than without its use.

[pt] Os mapas de características do compressor axial representam o desempenho deste por toda sua faixa de operação. Estes mapas podem ser utilizados para determinar o ponto de operação na simulação off-design. O presente trabalho propõe uma metodologia de manipulação de mapas de características de compressores axiais, baseada nas metodologias já existentes. A rotina desenvolvida, denominada PCOMP, é capaz de obter uma nova linha de rotação, entre duas linhas adjacentes conhecidas. A distância entre duas linhas adjacentes conhecidas e a nova linha irá determinar a influência que cada uma terá nas características desta nova linha. Uma vez determinada a linha de rotação, os parâmetros são interpolados a fim de determinar a vazão mássica corrigida e eficiência isentrópica para a razão de pressão correspondente, dada na entrada da rotina. O método de ponderação para a determinação de novas linhas de rotação apresentou desvios menores que 3% para a vazão mássica corrigida e eficiência isentrópica. Comparando as saídas da rotina com dados de operação de uma usina real, foram encontrados desvios menores que 1% para a eficiência isentrópica. A rotina desenvolvida foi implementada no módulo de simulação do compressor da ferramenta de simulação de turbinas a gás denominada NGGT (Natural Gas & Gas Turbine), apresentando resultados satisfatórios. / [en] Axial compressor maps are able to represent the performance of all its operating range. These maps are used for determining the operating point in the off-design simulation. This thesis proposes a methodology for handling maps of axial compressors, based on existing methodologies. The model, called PCOMP, is able to obtain a new rotational speed line between two adjacent lines known. The distance between the known and the new line will determine the influence that each one will have in the characteristics of the new line. Once determined the speed line, one can find the operating point interpolating the known parameters to determine the corrected mass flow and isentropic efficiency for the corresponding pressure ratio given in the entry data of the routine. The weighting method using to determinate the new rotation speed line presented deviations smaller than 3% for the corrected mass flow and isentropic efficiency. By comparing the outputs of the developed code with the operating data of a real power plant, were found deviations smaller than 1% for the isentropic efficiency. The routine was successfully implemented in a gas turbine performance computer program, called NGGT (Natural Gas & Gas Turbine) model, which presented accurate and efficient simulations.

This paper presents the results of stator clocking investigations at a design point and an operating point near the stability limit in a low-speed research compressor (LSRC). The unsteady flow field of the LSRC at several clocking configurations was investigated using a three-dimensional unsteady, viscous solver. The unsteady pressure on the rotor blades at midspan (MS) was measured using time-resolving piezoresistive miniature pressure transducers. The effect of clocking on the unsteady pressure fluctuation at MS on the rotor blades is discussed for different operating points. Based on the unsteady profile pressures, the blade pressure forces were calculated. The peak-to-peak amplitudes of the unsteady blade pressure forces are presented and analysed for different clocking positions at both the design point and the operating point near the stability limit of the compressor.

The objective of this research is to investigate the effects of tip clearance on the stage and component performance in a high-speed centrifugal compressor. The experimental data were compared against results from a numerical model to assess the ability of the numerical simulation to predict the effects of tip clearance. Experimental data were collected at Purdue University on the Single Stage Centrifugal Compressor (SSCC), a high-speed, high-pressure ratio test compressor sponsored by Honeywell Aerospace. Numerical simulations were completed using the ANSYS CFX software suite and part of the research computing clusters located at Purdue University.<div><br></div><div>Two tip clearances were tested, the nominal tip clearance and a tip clearance that is 66% larger than the nominal clearance, at speeds from 60% to 100% corrected speed. To compare data points with different tip clearances, various parameters were evaluated, and one was chosen. The value of TPR/inlet corrected mass flow rate best represented similar loading conditions, and thus similar incidences, for each tip clearance and was chosen as the best method for comparing similar data points taken with different clearances. Stage and component performance were focused on the sensitivity of each performance parameter to the changing of the tip clearance. The stage total pressure ratio and stage efficiency showed moderate sensitivity while the stage work factor showed much lower sensitivity. The impeller is more sensitive to changing tip clearances than the stage is, showing greater changes when comparing data from each tip clearance. The diffuser was on the same order of sensitivity as the impeller, with marginally higher sensitivities for some parameters. It was found that by the typical performance metrics, the diffuser performs worse at the nominal clearance than at the larger clearance. Upon further investigation though, the impeller is providing a higher static pressure and therefore, more diffusion, at the nominal clearance so the diffuser must perform less diffusion during nominal clearance operation.<br></div><div><br></div><div>To assess the validity of a prediction of the performance and sensitivity of the stage and components to the tip clearance, a numerical model was developed and validated. The numerical model was able to reasonably predict the stage performance with better comparisons of performance in the impeller and worse in the diffuser. The instrumentation in the experiment was replicated in the software to calculate performance the same way it is calculated experimentally so that the results would be comparable. While the performance of the stage and components was lacking in some areas, the trends predicted were similar to those calculated from the experimental data. As with the performance, the trends in the impeller matched very well between the experiment and the numerical simulation. The trends in stage and diffuser performance were predicted more accurately than the stage and diffuser performance maps and were able to capture the magnitude of the change in performance caused by changing the tip clearance. <br></div>

The purpose of this master thesis is to provide a reliable methodology to predict the forced response of a monoblock bladed drum from a low pressure compressor. Pre-test forced response calculations have already been made at Techspace Aero in 2013. Now that experimental data are available, the methodology has to be adapted to ensure the best numerical-experimental correlation possible. The final goal is that, at the end of the thesis, engineers at Techspace Aero will be able to launch reliable forced response simulations within a short amount of time. For the sake of confidentiality, some data are not revealed, such as the engine name, some numerical values (forced response, aerodynamic damping, frequency of the mode etc…) and axis scales. In this paper, the study focuses on the forced response of a rotor blade from the first stage under the excitation from the upstream stator. The mode under investigation is the 2S2, the one that responded during the experiment. The TWIN approach is used to compute the forced response of the rotor blade. With this approach, a steady stage computation has first to be carried on as an initialization. Then two unsteady computations are necessary. The first, without blade motion, will provide the excitation aerodynamic forces. The aerodynamic damping will be extracted from the second one, where the motion of the blade is imposed on a given eigenmode. The forced response can then be computed with these two results and some additional structural data.  The results will be compared to the experimental value.

Abstract Compressor station (CS) is an essential and an integral part of gas pipeline, providing gastransportation by means of power equipment, installed at CS. It serves as a control element in thecomplex of buildings, belonging to the trunk gas pipeline. It is by compressor station operationparameters the pipeline operation mode is defined. Presence of CS allows to adjust an operation modeof the gas pipeline at gas consumption fluctuations, using the maximum of the gas pipeline storagecapacity.During the operation of compressor station there can occur some infractions of gas pumping unit(GPU) electro-receivers power supply, leading to a forced or emergency stop of at least one GPU ofCS. Wind power plants can be used as a backup power supply. Years of national and internationalexperience show that the use of wind power plants of low power (up to 5-6 kW) is almost alwayseconomically feasible in areas with average annual wind speed VAV. AN. of more than 3.5-4.0 m/s. Theuse of high-power wind power plants is justified in cases when VAV. AN. exceeds 5.5-6.0 m/s.In the master's thesis the possibility of wind power plants exploitation for uninterrupted operation ofauxiliary power plant (APP), which is a part of compressor station, is considered.In the first chapter of the thesis the condition and reliability of CS power supply system of trunk gaspipelines (TGP) is examined. Besides the issues of energy supply and gas facilities stability areconsidered; the categories of electrical receivers, as well as factors, providing the sustainability andreliability of compressor station, are defined. In the last section of this chapter the volumes of powerconsumption at compressor station and auxiliary power plant are considered.The second chapter provides a classification of wind turbines, their design and wind flowcharacteristics, as well as the methods for wind climatic characteristics determination at a giventerritory. Particular attention is paid to offshore wind turbines as the most promising wind energyinstallations.The third chapter presents environmental aspects of wind power industry: an impact on fauna, acousticnoise, vibration impact, radio waves interference, air pollution, land use, visual impact, tourism andrecreation zones.The fourth chapter represents the consideration of wind turbine exploitation, including thedevelopment of a wind energy project, the power generation base cost definition, as well as the ways toreduce the costs of power generation and prospects of development and usage of wind power industryin the Russian Federation.

This study analyzes the performance of variable capacity heat pump scroll compressor which is equipped with vapour injection and permanent magnet motor. Refrigerant used in the system is R410A. The study is divided in two phases. In first phase, tests are carried out for heat pump without vapour injection. Heat pump’s performance including COPs, heating/cooling capacities, inverter losses, heat transfer behaviour in condenser/evaporator are analyzed. Inverter losses increase but the ratio of inverter losses to the total compressor power decreases with increase in compressor speed. Electromechanical losses of compressor are much higher than the inverter losses and so make most part of the total compressor losses (summation of inverter and electromechanical losses). In second phase benefits of vapour injection are analyzed. For vapour injection, heat pump’s performance is evaluated for two different refrigerant charges: 1.15kg and 1.28kg. It is noted that heat pump performs better for refrigerant charge 1.15kg even at lower compressor speeds as compared to refrigerant charge 1.28kg. For refrigerant charge 1.15kg, heat pump COP cool with vapour injection increases by an average of 10.66%, while COP heat increases by an average of 9.4%, at each compressor speed except for 30Hz, as compared to conventional heat pump cycle with no vapour injection. Similarly refrigerant temperature at outlet of compressor also reduces with vapour injection which leads to the better performance of heat pump.

As the demand to improve the fuel efficiency of current commercial aircraft increases, new commercial airliner concepts such as the Blended Wing Body has been researched on and studied in various aspects over the years as an efficient alternative to the conventional transport configuration. One particular aspect of the Blended Wing Body is the use of the propulsive fuselage concept. In this concept, the fuselage boundary layer is ingested by the engine and this is aimed at producing benefits such as improved fuel efficiency, reduced ram drag as well as lower structural weight of the engine. During the ingestion process, the low momentum boundary layer is re-energized by the propulsion system before exiting into the atmosphere. In this way, the ingested flow does not contribute to the wake deficit and hence, the overall drag of the aircraft is reduced. Since thrust equal drag in steady and level flight, and power is equal to thrust multiplied by velocity, the reduction in drag implies a reduction in the power required to drive the vehicle.In essence, the ingestion of the boundary layer which leads to a lower inlet stagnation pressure represents a direct thermodynamic penalty. However, the momentum deficit captured by the engine represents a drag reduction to the aircraft. In this way, the propulsion system performance suffers a decrease in engine efficiency while the aircraft drag is reduced in proportion to the amount of boundary layer flow that is ingested. Therefore, a trade-off exists between the increase in aircraft drag reduction and the decrease in engine performance as more boundary layer is consumed. Another important concern is the significant flow distortion which can lead to increased vibration and fatigue of the fan and compressor blades in particular. This flow distortion is characterized by the distortion coefficient, a standard widely used in the aircraft engine industry. While it was found that the ingestion of the boundary layer can provide a decrease in fuel burn of several percentages, the benefits of boundary layer ingestion have shown to be very sensitive to the magnitude of the fan and duct losses. Hence, it is crucial that fan designers are able to design new rotor blades that are able to withstand the flow distortion while ensuring that engine performance degradation is kept to a minimum in order to maximize the overall gain in fuel efficiency.The main aim of this research is therefore to understand and analyse the rotor performance under both uniform and non-uniform inflow condition. This will then provide insights into the main fluid mechanism affecting rotor performance under such conditions. As such, the early phase of this research was focused on the development of an in-house blade modeller which was then later used in the parametrization and reconstruction of the NASA Rotor 67. Other than the development of the Blade Modeller, this research was also focused on the coupling of an open-source meshing software, SALOME to the Blade modeller which will then allow the user to achieve automated meshing needed for the design optimization process. The main highlight of this thesis is on the detailed analysis of the blade to blade domain as well as the overall rotor performance under non uniform inflow condition.

A significant part of the environmental impact of a heat pump isgenerally related to the direct emission of the refrigerant fluid during thelife time of the machine. Although the Montreal Protocol has alreadylargely secured its status as a success story by cutting the ozone deplentationrefrigerants drastically, we still have to deal with the challengesresulting from climate change.Natural refrigerants such as Propane permits to design more ecofriendlysystem without sacrificing the performance of the machine. Thethesis work is part of a European project called Next Generation of HeatPumps working with Natural fluids (NxtHPG) whose primary aim is thedevelopment of heat pumps working with Natural refrigerant that aresafe, reliable, with high efficiency and high capacity. Royal Institute oftechnology (KTH) is one of the partner of the project and responsiblefor the experimental campaign of two large propane heat pumps: an airsource heat pump (Case 1 ) and a ground source heat pump suitablefor boreholes (Case 2 ). Few cases in literature report on studies aboutlarge capacity heat pumps using propane as refrigerant.This thesis project focuses on the experimental evaluation of theCase 2 from an energy point view. The safety issues about the use of flammable refrigerant, i.e propane, are briefly reported; however theyare not considered strictly part of the thesis work since they are coveredin other phases of NxtHPG project. Experimental tests for Case 1 werenot conducted during this thesis work because of delays in the prototypedelivery from the manufacturer. However, concerns about the hydraulicloop of the test rig of both the heat pumps was identified and a newdesign was suggested and implemented.During the experimental campaign for Case 2 a significant numberof tests were performed according to a specific text matrix definedfrom the EN 14285 standard. A simple heat pump model has beenused to evaluate the overall performance of the machine from the directmeasurements. The heat pump components (compressors, condenser,evaporator, expansion valve) have been analysed in details by definingspecific analysis model for each one. The results have been comparedwith the manufacture expectation.The prototypes demonstrated to have potentially very good performance,since in the first set of tests the machine behaved as expectedby the IMST-ART software. On the other hand, a drop of the unitefficiency and capacity have been registered during the experimentalcampaign for similar working condition. Two different explanations areinvestigated to clarify the strange phenomenon. The first hypothesisconsiders minor internal damage in the compressor, as check valve leakage;consequence of the use of the compressor in a tandem layout. Itgenerates a back-flow in the non working compressor. The second explanationregards inert gas infiltration in the system. On the otherhand they are not able to explain entirely the system issues and theyneed to be confirmed by the manufacturer analysis of the open compressor.The further improvements, proposed and discussed with themanufacture companies involved, can help to solve the question markson the strange system behaviour during the future work. The nextexperimental campaign for Case 1 that will start on April 2015.The software IMST-ART, used to predict the performance of theheat pump, is demonstrated to be a fast and useful tool. The model ofthe software for propane as refrigerant and brazed plate heat exchangerpredicts adequately the experimental measurement. / Una parte significativa dell’impatto ambientale relativo a una pompadi calore è legato alle emissioni dirette di refrigerante durante ilperiodo di vita della macchina. Nonostante l’accordo di Montreal siagià stato considerato come un successo storico per il drastico taglio deirefrigeranti dannosi per lo strato di ozono, bisogna ancora fronteggiarele sfide relative al cambiamento climatico.Refrigeranti naturali, come il Propano, permettono di realizzaremacchine più ambientalmente compatibili senza però sacrificare le prestazionidella macchina stessa. Questo lavoro di tesi fa parte di unprogetto Europeo chiamato Next Generation of Heat Pumps workingwith Natural fluids (NxtHPG), in cui obiettivo primario è quello di svilupparepompe di calore che lavorano con fluidi Naturali che allo stessotempo siano sicure, affidabili, con elevata efficienza e taglia.Royal Institute of technology (KTH) è uno dei partner del progettoe anche responsabile della campagna sperimentale di due pompe dicalore a propano di grossa taglia: una pompa ad aria Case 1 e unageotermicaCase 2. Sono pochi gli esempi in letteratura che riguardanolo studio di macchine di questo tipo di grande taglia, questo costituiscela novità del lavoro.Il lavoro di tesi presentato è incentrato principalmente sulla valutazionesperimentale da un punto di vista energetico di Case 2. Leproblematiche legate alla sicurezza legate all’utilizzo di refrigeranti infiammabili,quale è il propano, sono solo citate; d’altra parte non sonoconsiderate strettamente facenti parte del lavoro di tesi in quando altrefasi del progetto NxtHPG sono incentrate su questo argomento.Misure sperimentali per Case 1 non sono state condotte durante illavoro di tesi a causa di ritardi nella consegna dei prototipi da parte dell’aziendaproduttrice. Ad ogni modo sono stati individuate problematichelegate ai circuiti idraulici dell’installazione sperimentale di entrambele pompe di calore e successivamente risolte con l’implementazione diuna nuova proposta di circuito idraulico.Durante la campagna sperimentale di Case 2, sono stati svolti undiscreto numero di misurazioni secondo una ben specifica test matrixderivata dalla normativa europea EN 14285. Un semplice modello dipompa di calore è stato utilizzato per la valutazione delle prestazionigenerali della macchina a partire dalle misurazioni dirette. I componenti della pompa di calore, quali compressore, condensatore, evaporatore,valvola di espansione, sono state analizzati separatamente definendouno specifico modello per ognuno di essi e comparato con i risultatiattesi dai produttori.Il prototipo di Case 2 dimostra avere ottime potenzialità come prestazioni,in quanto, durante il primo set di test, il comportamento dellamacchina era in linea con le previsioni del software IMST-ART. D’altraparte, durante la campagna sperimentale, si è evidenziato un fortecalo delle prestazioni nonostante le condizioni di funzionamento fosseropressoché simili. Per spiegare questa anomalia, due differenti ipotesisono state formulate. La prima assume la presenza di di deterioramentiminori nel compressore, come perdite nella valvola di non ritorno (checkvalve), conseguente ad l’utilizzo in configurazione tandem. Si genererebbeun flusso riverso di refrigerante nel compressore non funzionante.La seconda ipotesi riguarda infiltrazione di gas inerte all’interno dellamacchina. D’altra parte tali ipotesi non sono in grado di spiegareinteramente le problematicità nel sistema e hanno necessità di essereconfermate dall’analisi a compressore aperto da parte della aziendaproduttrice.Successivi perfezionamento dei prototipi sono stati proposti e discussicon le aziende produttrici coinvolte, e questo permetterebbe dirispondere ai punti di domanda riguardo lo strano comportamento delsistema. La prossima campagna sperimentale per Case 2 inizierà adAprile 2015. Il software IMST-ART, usato per predire le performancedella pompa di calore, ha dimostrato essere uno strumento veloce e utile.Il modello implementato nel software per il propano e per gli scambiatoridi calore a piatti predice adeguatamente le misure sperimentali. / Next Generation of Heat Pumps working with Natural fluids (NxtHPG)

Historically, compression was primarily used as a preventative measure to reduce the risk of clipping or overloading equipment in the recording signal chain. Research on the topic has revealed that modern production applications more commonly include utilizing compression as a creative effect, to impart distortion, manipulate timbre, and modify transients, rather than to control the dynamic range of audio signals. It has also been found that specific compressors are regularly chosen for the sonic signatures that they impart onto audio material. To evaluate the quality of a digitally modeled emulation plugin of a classic compressor, an analog and digital version of the Universal Audio 1176 FET compressor was tested in this study. 20 experienced listeners participated in a MUSHRA-style listening test during which processed sounds were rated based on four attributes. The result of the listening test verifies previous findings on the sonic signature of the 1176, and evidence presented suggests that the plugin can be used for the same creative purposes as the analog device. However, it was also found that intuitive methods could not be used when trying to match the processing of the hardware. Instead, critical listening and user experience seem to be important factors when trying to achieve the same creative effects when using the software plugin.