A two-dimensional thin-layer Navier-Stokes cascade flow solver for turbomachinery is developed. A second-order finite-difference scheme and a second and fourth-difference dissipation scheme are used. Periodic and non-reflecting inlet and outlet boundary conditions are implemented into the approximate-factorization numerical method. Turbulence is modeled through the one-equation Spalart-Allmaras model. A two-dimensional turbomachinery cascade structured grid generator is developed to produce six-block H-type grids. The validity of this work is tested in various ways. A grid convergence study is performed showing the effect of grid density. The non-reflecting inlet and outlet boundary conditions are tested for boundary placement influence. Comparisons of the flow solver numerical results are performed against experimental results. A Mach number sweep and angle of attack sweep are performed on two similar transonic turbine cascades.

This research presents a detailed study of non-synchronous vibration (NSV) and the development of an efficient design method for NSV. NSV occurs as a result of the complex interaction of an aerodynamic instability with blade vibrations. Two NSV design methods are considered and applied to three test cases: 2-D circular cylinder, 2-D airfoil cascade tip section of a modern compressor, and 3-D high pressure compressor cascade that encountered NSV in rig testing. The current industry analysis method is to search directly for the frequency of the instability using CFD analysis and then compare it with a fundamental blade mode frequency computed from a structural analysis code. The main disadvantage of this method is that the blades' motion is not considered and therefore, the maximum response is assumed to be when the blade natural frequency and fluid frequency are coincident. An alternate approach, the enforced motion method, is also presented. In this case, enforced blade motion is used to promote lock-in of the blade frequency to the fluid natural frequency at a specified critical amplitude for a range of interblade phase angles (IBPAs). For the IBPAs that are locked-on, the unsteady modal forces are determined. This mode is acceptable if the equivalent damping is greater than zero for all IBPAs. A method for blade re-design is also proposed to determine the maximum blade response by finding the limit cycle oscillation (LCO) amplitude. It is assumed that outside of the lock-in region is an off-resonant, low amplitude condition. A significant result of this research is that for all cases studied herein, the maximum blade response is not at the natural fluid frequency as is assumed by the direct frequency search approach. This has significant implications for NSV design analysis because it demonstrates the requirement to include blade motion. Hence, an enforced motion design method is recommended for industry and the current approach is of little value. / Dissertation

This dissertation provides numerical studies to improve bladed disk assembly design for preventing blade high cycle fatigue failures. The analyses are divided into two major subjects. For the first subject presented in Chapter 2, the mechanisms of transonic fan flutter for tuned systems are studied to improve the shortcoming of traditional method for modern fans using a 3D time-linearized Navier-Stokes solver. Steady and unsteady flow parameters including local work on the blade surfaces are investigated. It was found that global local work monotonically became more unstable on the pressure side due to the flow rollback effect. The local work on the suction side significantly varied due to nodal diameter and flow rollback effect. Thus, the total local work for the least stable mode is dominant by the suction side. Local work on the pressure side appears to be affected by the shock on the suction side. For the second subject presented in Chapter 3, sensitivity studies are conducted on flutter and forced response due to frequency mistuning and aerodynamic asymmetry using the single family of modes approach by assuming manufacturing tolerance. The unsteady aerodynamic forces are computed using CFD methods assuming aerodynamic symmetry. The aerodynamic asymmetry is applied by perturbing the influence coefficient matrix. These aerodynamic perturbations influence both stiffness and damping while traditional frequency mistuning analysis only perturbs the stiffness. Flutter results from random aerodynamic perturbations of all blades showed that manufacturing variations that effect blade unsteady aerodynamics may cause a stable, perfectly symmetric engine to flutter. For forced response, maximum blade amplitudes are significantly influenced by the aerodynamic perturbation of the imaginary part (damping) of unsteady aerodynamic modal forces. This is contrary to blade frequency mistuning where the stiffness perturbation dominates. / Dissertation

Axial compressors are widely used in many aerodynamic applications. The design of an axial compressor configuration presents many challenges. Until recently, compressor design was done using 2-D viscous flow analyses that solve the flow field around cascades or in meridional planes or 3-D inviscid analyses. With the advent of modern computational methods it is now possible to analyze the 3-D viscous flow and accurately predict the performance of 3-D multistage compressors. It is necessary to retool the design methodologies to take advantage of the improved accuracy and physical fidelity of these advanced methods. In this study, a first-principles based multi-objective technique for designing single stage compressors is described. The study accounts for stage aerodynamic characteristics, rotor-stator interactions and blade elastic deformations. A parametric representation of compressor blades that include leading and trailing edge camber line angles, thickness and camber distributions was used in this study A design of experiment approach is used to reduce the large combinations of design variables into a smaller subset. A response surface method is used to approximately map the output variables as a function of design variables. An optimized configuration is determined as the extremum of all extrema. This method has been applied to a rotor-stator stage similar to NASA Stage 35. The study has two parts: a preliminary study where a limited number of design variables were used to give an understanding of the important design variables for subsequent use, and a comprehensive application of the methodology where a larger, more complete set of design variables are used. The extended methodology also attempts to minimize the acoustic fluctuations at the rotor-stator interface by considering a rotor-wake influence coefficient (RWIC). Results presented include performance map calculations at design and off-design speed along with a detailed visualization of the flow field at design and off-design conditions. The present methodology provides a way to systematically screening through the plethora of design variables. By selecting the most influential design parameters and by optimizing the blade leading edge and trailing edge mean camber line angles, phenomenon s such as tip blockages, blade-to-blade shock structures and other loss mechanisms can be weakened or alleviated. It is found that these changes to the configuration can have a beneficial effect on total pressure ratio and stage adiabatic efficiency, thereby improving the performance of the axial compression system. Aeroacoustic benefits were found by minimizing the noise generating mechanisms associated with rotor wake-stator interactions. The new method presented is reliable, low time cost, and easily applicable to industry daily design optimization of turbomachinery blades.

Metal mesh foil bearings (MMFBs) are a promising low cost gas bearing technology for support of high speed oil-free microturbomachinery. Elimination of complex oil lubrication and sealing system by installing MMFBs in oil free rotating machinery offer distinctive advantages such as reduced system overall weight, enhanced reliability at high rotational speeds and extreme temperatures, and extended maintenance intervals compared to conventional turbo machines. MMFBs for oil-free turbomachinery must demonstrate adequate load capacity, reliable rotordynamic performance, and low frictional losses in a high temperature environment. The thesis presents the measurements of MMFB break-away torque, rotor lift off and touchdown speeds, temperature at increasing static load conditions, and identified stiffness and equivalent viscous damping coefficients. The experiments, conducted in a test rig driven by an automotive turbocharger turbine, demonstrate the airborne operation (hydrodynamic gas film) of the floating test MMFB with little frictional loses at increasing loads. The measured drag torque peaks when the rotor starts and stops, and drops significantly once the bearing is airborne. The estimated rotor speed for lift-off increases linearly with increasing applied loads. During continuous operation, the MMFB temperature measured at one end of the back surface of the top foil increases both with rotor speed and static load. Nonetheless, the temperature rise is only nominal ensuring reliable bearing performance. Application of a sacrificial layer of solid lubricant on the top foil surface aids to reduce the rotor break-away torque. The measurements give confidence on this simple bearing technology for ready application into oil-free turbomachinery. Impact loads delivered (with a soft tip) to the test bearing, while resting on the (stationary) drive shaft, evidence a system with large damping and a structural stiffness that increases with frequency (max. 200 Hz). The system equivalent viscous damping ratio decreases from ~ 0.7 to 0.2 as the frequency increases. In general, the viscous damping in a metal mesh structure is of structural type and inversely proportional to the frequency and amplitude of bearing motion relative to the shaft. Impact load tests, conducted while the shaft rotates at 50 krpm, show that the bearing direct stiffness is lower (~25% at 200 Hz) than the bearing structural stiffness identified from impact load tests without shaft rotation. However, the identified equivalent viscous damping coefficients from tests with and without shaft rotation are nearly identical. The orbits of bearing motion relative to the rotating shaft show subsynchronous motion amplitudes and also backward synchronous whirl. The subsynchronous vibration amplitudes are locked at a frequency, nearly identical to a rotor natural frequency. A backward synchronous whirl occurs while the rotor speed is between any two natural frequencies, arising due to bearing stiffness asymmetry.

Torsional vibration is an oscillatory angular twisting motion in the rotating members of a system. It can be deemed quite dangerous in that it cannot be detected as easily as other forms of vibration, and hence, subsequent failures that it leads to are often abrupt and may cause direct breakage of the shafts of the drive train. The need for sufficient analysis during the design stage of a rotating machine is, thus, well justified in order to avoid expensive modifications during later stages of the manufacturing process. In 1998, a project was initiated by the Turbomachinery Research Consortium (TRC) at Texas A&M University, College Station, TX, to develop a suite of computer codes to model torsional vibration of large drive trains. The author had the privilege of developing some modules in Visual Basic for Applications (VBA-Excel) for this suite of torsional vibration analysis codes, now collectively called XLTRC-Torsion. This treatise parleys the theory behind torsional vibration analysis using both the Transfer Matrix approach and the Finite Element approach, and in particular, validates the results generated by XLTRC-Torsion based on those approaches using experimental data available from tests on a 66,000 HP Air Compressor.

<p>Siemens Industrial Turbomachinery AB (SIT AB) i Finspång är ett företag vars verksamhet är inriktad på tillverkning av gas- och ångturbiner för främst industriella tillämpningsområden. Företaget har cirka 2 100 anställda och är en del av den tyska storkoncernen Siemens AG. Inom SIT AB har det sedan tidigare funnits en delad mening kring vilka orsaker som främst bidrar till förluster inom företagets produktion. I dagsläget genomförs flera olika typer av driftsuppföljningar, ett problem är dock att dessa inte är synkroniserade för att ge en tydlig förlustbild på maskinspecifik nivå. Till följd av detta önskar nu produktionsansvariga på SIT AB undersöka möjligheten att mäta utrustningseffektiviteten hos sina maskinresurser genom införande av mätetalet Overall Equipment Effectiveness (OEE). Genom ett pilotprojekt ska en metod för mätning av OEE på SIT AB utvecklas, denna ska sedan implementeras och testas på två av företagets fleroperationsmaskiner. Pilotprojektet genomförs i form av ett examensarbete, arbetet ska ligga till grund för rekommendationer gällande hur mätresultaten ska användas samt hur SIT AB ska gå tillväga för att kunna genomföra OEE-mätningar i större skala.</p><p>OEE avser mätning av total utrustningseffektivitet genom ett enda mätetal. Syftet med beräkningen är att åskådliggöra omfattningen av de sex stora produktionsförluster som definieras inom ramen för Total Productive Maintenance. Efter förlustanalys kan välriktade förbättringsåtgärder vidtas med avsikt att öka utrustningseffektiviteten hos den studerade resursen.</p><p>Inom denna undersökning konstateras att OEE är ett mätetal som främst är framtaget för applikation i processliknande industrier. Eftersom SIT AB bedriver tillverkning i en huvudsakligen funktionell verkstadsmiljö krävs viss anpassning för att öka mätetalets tillämpbarhet på företaget. En sådan anpassning får även stöd i litteraturen där det klargörs att det är viktigare att åstadkomma en mätning som kan ligga till grund för förbättringsarbete än att strikt följa grunddefinitionen av OEE. Som stöd för metodanpassningen genomfördes en fallstudie på Kongsberg Terotech AS (KTT), ett av nordens ledande företag inom branschen för underhåll av verktygsmaskiner. KTT har stor erfarenhet inom OEE-mätning genom arbete som rådgivare på uppskattningsvis 15-20 olika företag där verksamhetsområdena sträcker sig från enstyckstillverkning till processindustri och från skärande bearbetning till livsmedelindustri.</p><p>Den metod som utvecklats för mätning av OEE på SIT AB är helt baserad på storheten tid. Mätningen sker genom tidsregistrering inom ett diskret antal fördefinierade förlustkategorier, framtagna specifikt för de studerade maskinerna. Genom utvecklandet av en specialdesignad blankett kan datainsamlingen skötas av maskinernas operatörer under pågående ordinarie arbete. Mätningarnas manuella utförande utgör ett hinder för exakt stopptidsmätning, konceptet kan dock införas med kort varsel och utan krav på dyra investeringar i avancerad mätutrustning.</p><p>På inrådan från KTT genomfördes OEE-mätning under en period om fyra veckor i respektive maskin. Förlustdata kunde insamlas från 95 av 96 möjliga skift och dataunderlaget omfattar 564 respektive 576 planerade produktionstimmar i vardera resurs. Trots att de båda fleroperationsmaskinerna i princip är identiska till utförandet uppvisades förlustbilder som i jämförelse är relativt olika. Av detta dras slutsatsen att maskinerna bör behandlas individuellt vid vidtagandet av eventuella förbättringsåtgärder.</p><p>OEE-mätning är något som enbart ska utföras i syfte att underlätta och motivera kontinuerligt förbättringsarbete kopplat till företagets tillverkningsprocesser. Den framtagna mätmetoden kan hjälpa SIT AB att värdera förbättringspotentialen hos den studerade produktionsutrustningen, insamlad data kan även användas för att prioritera hur förbättringsinsatserna ska fokuseras. Huvuddragen i metoden kan även användas för mätning i stor skala, förlustkategorier bör dock väljas utgående från den maskin där mätningarna ska introduceras. En tydlig nackdel är att metoden i nuvarande utförande inte säkerställer god kvalitet i insamlad data, detta kan innebära viss risk för att beslut fattas på felaktiga grunder. Metoden kan vara lämplig att använda som introduktion till OEE-mätning eller i det fall att företaget vill undvika mer omfattande investeringar kopplat till mätningarna. Om SIT AB i framtiden vill satsa på OEE-mätning rekommenderas att datainsamlingen automatiseras.</p><p>Det förbättringsarbete som ska följa av genomförda OEE-mätningar bör skötas av förbättringsgrupper tillsatta för ändamålet. Förbättringsgrupperna innehåller med fördel personal med olika kunskapsområden. En tvärfunktionell sammansättning bör innebära att förbättringsarbetet kan skötas på ett mer mångsidigt sätt än vid behandling av enskilda personalgrupper. Den viktigaste förutsättningen för ett lyckat förbättringsarbete är att alla beslut kan baseras på fakta från verkligheten, mätningar som exempelvis OEE utgör konkreta verktyg för att åstadkomma denna situation. För att kunna styra och förbättra centrala produktionsprocesser måste dessa ständigt utvärderas. I detta sammanhang kan införandet av OEE-mätning komma att spela en central roll för verksamheten på SIT AB.</p> / <p>Siemens Industrial Turbomachinery AB (SIT AB) in Finspong is a company dedicated to the production of gas- and steam turbines mainly for industrial applications. The company has around 2 100 employees and is a part of Siemens AG based in Germany. There have previously been different opinions regarding what the largest causes of losses within the company’s production are. Today a number of different ways to follow up on the production is used, a problem with these are however that they are not synchronized to give a clear view of the losses on any specific machine. As a result the production managers at SIT AB now want to look into the possibility of measuring the machines´ effectiveness by introduction of the technique Overall Equipment Effectiveness (OEE). A method for measuring OEE at SIT AB will be developed through a pilot study, this will then be implemented and tested on two of the company’s multifunctional machines. The pilot study is to be performed in the form of a master’s thesis, the paper will be the basis for recommendations regarding how the results of the measurements shall be used and how SIT AB should go about making the measurements usable on a grander scale.</p><p>OEE is used to show a resource’s total effectiveness with a single parameter. The calculations are aimed at illustrating to which extent the six big losses defined within Total Productive Maintenance affect the production. After the losses have been analysed improvement measures can be taken in order to increase the previously measured resource effectiveness.</p><p>Within this thesis it is concluded that OEE is developed mainly for use in mass-producing industries. Since SIT AB conducts production with similarities closer to a work-shop some adjustments have to be made in order to make OEE more applicable in the company. Such adjustments are supported by the literature where it is stated that it is more important to achieve a measurement which can be used as a basis for improvement rather then to strictly follow the original definition of OEE. As a support for the work with these adjustments a case study was conducted at Kongsberg Terotech AS (KTT), one of the leading companies regarding maintenance of tooling machines in the Nordic countries. KTT has gained a lot of experience when it comes to measuring OEE since they have worked as counsellors at approximately 15-20 different companies ranging from production of single units to mass-production and from metalwork to the food industry.</p><p>The method developed for the measurement of OEE at SIT AB is completely based on the entity time. The information is gathered by means of time being registered within a discrete number of predefined loss-categories designed specifically for the studied resources. Since a specially designed form is used the gathering of information can be performed by the operators during regular work. Exact registration of losses is hindered by the measurements being performed manually, however this allows the concept to be introduced with short notice and without the need of expensive investments regarding advanced equipment.</p><p>For manual data collecting KTT advised that the measurements should be performed for a period of four weeks in each machine. Data containing the losses could be gathered from 95 out of 96 shifts, which means observation of 564 and 576 planned production hours respectively in each machine. Despite the identical features of the multifunctional machines they presented different losses. This leads to the conclusion being drawn that all machines must be treated individually when it comes to deciding improvement measures.</p><p>Measuring OEE should only be carried out when the purpose is to create a basis for continuous improvement of the company’s production processes. The developed measuring technique can aid SIT AB in evaluating the potential for improvement of the studied equipment, the data can also be used to prioritize where improvement measures should be taken first. The main part of the technique can be used for measurements on a grander scale, the loss categories should however be chosen in accordance with the specific machine being studied. A clear down side is that the method in its current state does not secure good quality data, this can potentially mean that decisions are made based on false information. The method is suited for an introduction to OEE or if a company wants to avoid extensive investments. For the best possible result an automatic data collecting system is advised.</p><p>Improvement activities based on the OEE measurements should be carried out in groups appointed for the task. These groups should consist of staff with different areas of expertise, a cross functional composition will hopefully mean that the work with improvements can be undertaken in a versatile manner. The most important prerequisite for successful work with improvements is that all decisions are based on facts, measuring OEE can be used as a tool to present the reality. In order to be able to control and improve important production processes these must be constantly evaluated. In this context the introduction of OEE measurements can play an important role for the production system at SIT AB.</p>

Siemens Industrial Turbomachinery AB (SIT AB) i Finspång är ett företag vars verksamhet är inriktad på tillverkning av gas- och ångturbiner för främst industriella tillämpningsområden. Företaget har cirka 2 100 anställda och är en del av den tyska storkoncernen Siemens AG. Inom SIT AB har det sedan tidigare funnits en delad mening kring vilka orsaker som främst bidrar till förluster inom företagets produktion. I dagsläget genomförs flera olika typer av driftsuppföljningar, ett problem är dock att dessa inte är synkroniserade för att ge en tydlig förlustbild på maskinspecifik nivå. Till följd av detta önskar nu produktionsansvariga på SIT AB undersöka möjligheten att mäta utrustningseffektiviteten hos sina maskinresurser genom införande av mätetalet Overall Equipment Effectiveness (OEE). Genom ett pilotprojekt ska en metod för mätning av OEE på SIT AB utvecklas, denna ska sedan implementeras och testas på två av företagets fleroperationsmaskiner. Pilotprojektet genomförs i form av ett examensarbete, arbetet ska ligga till grund för rekommendationer gällande hur mätresultaten ska användas samt hur SIT AB ska gå tillväga för att kunna genomföra OEE-mätningar i större skala. OEE avser mätning av total utrustningseffektivitet genom ett enda mätetal. Syftet med beräkningen är att åskådliggöra omfattningen av de sex stora produktionsförluster som definieras inom ramen för Total Productive Maintenance. Efter förlustanalys kan välriktade förbättringsåtgärder vidtas med avsikt att öka utrustningseffektiviteten hos den studerade resursen. Inom denna undersökning konstateras att OEE är ett mätetal som främst är framtaget för applikation i processliknande industrier. Eftersom SIT AB bedriver tillverkning i en huvudsakligen funktionell verkstadsmiljö krävs viss anpassning för att öka mätetalets tillämpbarhet på företaget. En sådan anpassning får även stöd i litteraturen där det klargörs att det är viktigare att åstadkomma en mätning som kan ligga till grund för förbättringsarbete än att strikt följa grunddefinitionen av OEE. Som stöd för metodanpassningen genomfördes en fallstudie på Kongsberg Terotech AS (KTT), ett av nordens ledande företag inom branschen för underhåll av verktygsmaskiner. KTT har stor erfarenhet inom OEE-mätning genom arbete som rådgivare på uppskattningsvis 15-20 olika företag där verksamhetsområdena sträcker sig från enstyckstillverkning till processindustri och från skärande bearbetning till livsmedelindustri. Den metod som utvecklats för mätning av OEE på SIT AB är helt baserad på storheten tid. Mätningen sker genom tidsregistrering inom ett diskret antal fördefinierade förlustkategorier, framtagna specifikt för de studerade maskinerna. Genom utvecklandet av en specialdesignad blankett kan datainsamlingen skötas av maskinernas operatörer under pågående ordinarie arbete. Mätningarnas manuella utförande utgör ett hinder för exakt stopptidsmätning, konceptet kan dock införas med kort varsel och utan krav på dyra investeringar i avancerad mätutrustning. På inrådan från KTT genomfördes OEE-mätning under en period om fyra veckor i respektive maskin. Förlustdata kunde insamlas från 95 av 96 möjliga skift och dataunderlaget omfattar 564 respektive 576 planerade produktionstimmar i vardera resurs. Trots att de båda fleroperationsmaskinerna i princip är identiska till utförandet uppvisades förlustbilder som i jämförelse är relativt olika. Av detta dras slutsatsen att maskinerna bör behandlas individuellt vid vidtagandet av eventuella förbättringsåtgärder. OEE-mätning är något som enbart ska utföras i syfte att underlätta och motivera kontinuerligt förbättringsarbete kopplat till företagets tillverkningsprocesser. Den framtagna mätmetoden kan hjälpa SIT AB att värdera förbättringspotentialen hos den studerade produktionsutrustningen, insamlad data kan även användas för att prioritera hur förbättringsinsatserna ska fokuseras. Huvuddragen i metoden kan även användas för mätning i stor skala, förlustkategorier bör dock väljas utgående från den maskin där mätningarna ska introduceras. En tydlig nackdel är att metoden i nuvarande utförande inte säkerställer god kvalitet i insamlad data, detta kan innebära viss risk för att beslut fattas på felaktiga grunder. Metoden kan vara lämplig att använda som introduktion till OEE-mätning eller i det fall att företaget vill undvika mer omfattande investeringar kopplat till mätningarna. Om SIT AB i framtiden vill satsa på OEE-mätning rekommenderas att datainsamlingen automatiseras. Det förbättringsarbete som ska följa av genomförda OEE-mätningar bör skötas av förbättringsgrupper tillsatta för ändamålet. Förbättringsgrupperna innehåller med fördel personal med olika kunskapsområden. En tvärfunktionell sammansättning bör innebära att förbättringsarbetet kan skötas på ett mer mångsidigt sätt än vid behandling av enskilda personalgrupper. Den viktigaste förutsättningen för ett lyckat förbättringsarbete är att alla beslut kan baseras på fakta från verkligheten, mätningar som exempelvis OEE utgör konkreta verktyg för att åstadkomma denna situation. För att kunna styra och förbättra centrala produktionsprocesser måste dessa ständigt utvärderas. I detta sammanhang kan införandet av OEE-mätning komma att spela en central roll för verksamheten på SIT AB. / Siemens Industrial Turbomachinery AB (SIT AB) in Finspong is a company dedicated to the production of gas- and steam turbines mainly for industrial applications. The company has around 2 100 employees and is a part of Siemens AG based in Germany. There have previously been different opinions regarding what the largest causes of losses within the company’s production are. Today a number of different ways to follow up on the production is used, a problem with these are however that they are not synchronized to give a clear view of the losses on any specific machine. As a result the production managers at SIT AB now want to look into the possibility of measuring the machines´ effectiveness by introduction of the technique Overall Equipment Effectiveness (OEE). A method for measuring OEE at SIT AB will be developed through a pilot study, this will then be implemented and tested on two of the company’s multifunctional machines. The pilot study is to be performed in the form of a master’s thesis, the paper will be the basis for recommendations regarding how the results of the measurements shall be used and how SIT AB should go about making the measurements usable on a grander scale. OEE is used to show a resource’s total effectiveness with a single parameter. The calculations are aimed at illustrating to which extent the six big losses defined within Total Productive Maintenance affect the production. After the losses have been analysed improvement measures can be taken in order to increase the previously measured resource effectiveness. Within this thesis it is concluded that OEE is developed mainly for use in mass-producing industries. Since SIT AB conducts production with similarities closer to a work-shop some adjustments have to be made in order to make OEE more applicable in the company. Such adjustments are supported by the literature where it is stated that it is more important to achieve a measurement which can be used as a basis for improvement rather then to strictly follow the original definition of OEE. As a support for the work with these adjustments a case study was conducted at Kongsberg Terotech AS (KTT), one of the leading companies regarding maintenance of tooling machines in the Nordic countries. KTT has gained a lot of experience when it comes to measuring OEE since they have worked as counsellors at approximately 15-20 different companies ranging from production of single units to mass-production and from metalwork to the food industry. The method developed for the measurement of OEE at SIT AB is completely based on the entity time. The information is gathered by means of time being registered within a discrete number of predefined loss-categories designed specifically for the studied resources. Since a specially designed form is used the gathering of information can be performed by the operators during regular work. Exact registration of losses is hindered by the measurements being performed manually, however this allows the concept to be introduced with short notice and without the need of expensive investments regarding advanced equipment. For manual data collecting KTT advised that the measurements should be performed for a period of four weeks in each machine. Data containing the losses could be gathered from 95 out of 96 shifts, which means observation of 564 and 576 planned production hours respectively in each machine. Despite the identical features of the multifunctional machines they presented different losses. This leads to the conclusion being drawn that all machines must be treated individually when it comes to deciding improvement measures. Measuring OEE should only be carried out when the purpose is to create a basis for continuous improvement of the company’s production processes. The developed measuring technique can aid SIT AB in evaluating the potential for improvement of the studied equipment, the data can also be used to prioritize where improvement measures should be taken first. The main part of the technique can be used for measurements on a grander scale, the loss categories should however be chosen in accordance with the specific machine being studied. A clear down side is that the method in its current state does not secure good quality data, this can potentially mean that decisions are made based on false information. The method is suited for an introduction to OEE or if a company wants to avoid extensive investments. For the best possible result an automatic data collecting system is advised. Improvement activities based on the OEE measurements should be carried out in groups appointed for the task. These groups should consist of staff with different areas of expertise, a cross functional composition will hopefully mean that the work with improvements can be undertaken in a versatile manner. The most important prerequisite for successful work with improvements is that all decisions are based on facts, measuring OEE can be used as a tool to present the reality. In order to be able to control and improve important production processes these must be constantly evaluated. In this context the introduction of OEE measurements can play an important role for the production system at SIT AB.

The steady flow aerodynamics of a cascade of compressor airfoils is computed using a two-dimensional thin layer Navier-Stokes flow solver. The Dhawan and Narasimha transition model and Mayle‟s transition length model were implemented in this flow solver so that transition from laminar to turbulent flow could be included in the computations. A method to speed up the convergence of the fully turbulent calculations has been introduced. In addition, the effect of turbulence production formulations and including streamline curvature correction in the Spalart-Allmaras turbulence model on the transition calculations is studied. These transitional calculations are correlated with the low and high incidence angle experimental data from the NASA-GRC Transonic Flutter Cascade. Including the transitional flow showed a trendwise improvement in the correlation of the computational predictions with the pressure distribution experimental data at the high incidence angle condition where a large separation bubble existed in the leading edge region of the suction surface.

Neste trabalho é realizada a concepção, projeto, construção e ensaio de turbinas de múltiplos discos para a verificação dos principais parâmetros e metodologias utilizadas para o projeto e análise do equipamento, além de estudar formas de otimização do equipamento. Assim, uma turbina de múltiplos discos é construída e testada com diferentes configurações de rotores, em uma bancada experimental construída e dimensionada especialmente para esse fim, além da implementação dos métodos analíticos pesquisados no software Engineering Equation Solver (EES). Assim, uma comparação entre os resultados experimentais obtidos por Rice e os modelos de analíticos disponíveis, mostra que o modelo do fator de atrito (FA) é o que melhor representa a operação do equipamento, além de ser o mais versátil dos métodos testados, permitindo que a turbina seja dimensionada e otimizada para várias configurações de construção. Já os resultados experimentais obtidos com um dos protótipos de turbina construído e operado com ar comprimido, mostram que, com modificações simples da geometria, configuração e acabamento superficial dos discos que compõem o rotor, é possível aumentar a eficiência isentrópica em até 35% em relação a turbina padrão montada com a configuração padrão de rotor (discos lisos), sem acarretar prejuízo em alguns dos principais benefícios da utilização deste tipo de equipamento. Os resultados experimentais obtidos mostram também que a eficiência diminui significativamente com o aumento da folga entre o raio externo do rotor e a parte interna da carcaça. / This work is performed conception, design, construction and testing of multiple-disks turbines (MDTs) for the verification of key parameters and methodologies used for the design and analysis of machine as well as consider ways to equipment optimization. Thus, a multiple-disk turbine is constructed and tested with different impeller configurations, in a test rig especially constructed and dimensioned for this purpose, besides the implementation of the analytical methods in software Engineering Equation Solver (ESS). Thus, a comparison between the experimental results obtained by Rice and analytical models available, shows that the friction factor model (FF) is what best represents the operation of the equipment, and is the most versatile of the tested methods, allowing the turbine is sized and optimized for various building configurations. Since the experimental results obtained with one of the turbine prototypes built and operated with compressed air, show that with simple modifications of geometry, configuration and surface finish of the disks that make up the rotor, it is possible to increase the isentropic efficiency by up to 35% compared the standard turbine rotor mounted with the default configuration (flat disks), without causing damage in some of the major benefits of using this type of equipment. The experimental results also show that efficiency decreases significantly with increasing clearance between the outer radius of the rotor and the internal part of the housing.