Centrifugalne ili radijalne pumpe su podskupina dinamickih turbopumpi. Služe za podizanje energet... more Centrifugalne ili radijalne pumpe su podskupina dinamickih turbopumpi. Služe za podizanje energetske razine fluida u cilju postizanja određenog protoka ili visine dobave. Visina dobave pumpe trosi se na savladavanje geodetske visine između razina u spremnicima i visine gubitaka u cjevovodima. Radna tocka pumpe je ravnotežno stanje energije koju pumpa predaje radnom fluidu i energije koju trosi sustav na savladavanje geodetske visine i hidrodinamickih otpora. Prakticno, radna tocka nalazi se u sjecistu karakteristike sustava (cjevovoda) na kojeg je pumpa prikljucena i karakteristike pumpe prikazanima u dijagramu visina dobave-protok (Q-H dijagramu). U ovome radu prikazana je simulacija strujanja fluida u dvije razlicite konstrukcije centrifugalnih pumpi. Za simulacije su koristeni spregnuti i odvojeni rjesavac za nestlaciva strujanja iz paketa otvorenog koda OpenFOAM. Uspoređena je konvergencija rjesavaca za polja brzine i tlaka te za visinu dobave pumpe. Radne tocke dobivene simulac...
Optimizacija je disciplina numericke matematike za unaprijeđivanje rada sustava ili procesa da bi... more Optimizacija je disciplina numericke matematike za unaprijeđivanje rada sustava ili procesa da bi rezultati bili najbolji moguci. Optimizacijski algoritmi za zadacu imaju minimizaciju ili maksimizaciju funkcije cilja koja se proracunava simulacijom, uz odgovarajuca ogranicenja varijabli. U radu su opisani parametri i postavke optimizacije po visestrukim funkcijama cilja sa ogranicenjima varijabli cijevnog izmjenjivaca topline. Traže se optimalne pozicije cijevi kako bi se povecao prirast temperature fluida uz sto manji pad tlaka u izmjenjivacu. temperaturni prirast i pad tlaka su ujedno i funkcije cilja za ovaj problem. Za optimizaciju su koristena tri racunalna alata: open source alat Salome za konstrukciju geometrije, open source paket za racunalnu dinamiku fluida OpenFOAM i open source software za optimizaciju Dakota. Ispitivani su razliciti parametri genetskog algoritma za optimizaciju po visestrukim funkcijama cilja te su rezultati prikazani preko Pareto linija. Provedena je i ...
An automated process for turbine blade optimisation coupled with CFD is presented in this study. ... more An automated process for turbine blade optimisation coupled with CFD is presented in this study. A large number of turbine blade shapes is considered in the optimisation process, thus a large number of corresponding computational meshes would have to be used for CFD calculations. It has been well documented that local mesh resolution and mesh quality is one of principal sources of discretisation error in CFD. For consistent results in optimisation studies it is essential to control the absolute value and distribution of mesh- induced errors, ideally by employing a family of self-similar meshes. This is not easily achieved where the automated optimisation loop involves the use of an external or automatic mesh generator. In this study, a procedure of geometry variation in the CFD mesh is performed using a mesh morphing procedure, where the existing mesh will be automatically deformed to accommodate boundary deformation. Mesh morphing not only simplifies the optimisation loop but also ...
CFD simulation results for self propelled full scale ship are compared to sea trial measurements ... more CFD simulation results for self propelled full scale ship are compared to sea trial measurements in this work. Two–phase RANS based CFD numerical model used in this work is based on the Ghost Fluid Method for numerically robust treatment of discontinuities at the free surface and the algebraic Volume–of–Fluid method for interface capturing. The propeller is modelled as a pressure–jump based actuator disc, allowing CPU time efficient simulations while preserving the accuracy of integral results. The numerical model is implemented in foam–extend, a community driven fork of the OpenFOAM software. The comparison with sea trials includes achieved forward speed, thrust and torque for given shaft speed (in RPM) for a general cargo carrier.
This paper presents the performance of the implicitly coupled pressure-velocity solver for severa... more This paper presents the performance of the implicitly coupled pressure-velocity solver for several car aerodynamics cases: flow around a bluff body with a diffuser section, rotating wheel, generic car and Formula 1 front wing.
Strucne analize pokazuju da Republika Hrvatska raspolaže velikim energetskim resursima biomase iz... more Strucne analize pokazuju da Republika Hrvatska raspolaže velikim energetskim resursima biomase iz poljoprivrede, vocarstva i sumarstva. Buduci da se vise od 50% ovih resursa nalazi u ravnicarskom dijelu, a nesto manje u brdskim dijelovima, moguce je gradnjom malih kogeneracijskih elektrana na biomasu zadovoljiti veliki dio vlastitih potreba lokalnih zajednica za elektricnom i toplinskom energijom. Studije isplativosti su pokazale da je optimalna elektricna snaga termoelektrane 1 do 2 MW i oko 4 do 8 MW toplinske snage. U okviru rada predložena je toplinska shema jedne takve kogeneracijske termoelektrane, a na temelju potrebne elektricne snage izracunat je potrebni maseni protok pare na ulazu u turbinu. Prikazan je termodinamicki i aerodinamicki proracun turbine, odabrani su profili lopatica te izracunati gubici svih stupnjeva te snaga turbine.
Turbomachinery CFD has been extensively used for decades and variety of tools have been developed... more Turbomachinery CFD has been extensively used for decades and variety of tools have been developed for dealing with specific phenomena appearing in these machines. The tools enable significant computational savings, or provide simplified models for preliminary evaluation, which resulted in establishing CFD as a common, efficient R&D technique in industry. In this paper we present the methods for modeling complex flows inside various types of turbomachinery. A general overview of tools for turbomachinery simulations available in foam-extend is given, with the application demonstrated for both incompressible and compressible flow problems. Appropriate methods should be chosen depending on the physics and geometry involved: • steady-state or transient approach, • single blade passage or full annulus configuration, • type of rotor-stator interaction interface, • compressible or incompressible problem, • implicitly block–coupled or segregated pressure-velocity system, etc. All options wil...
In this paper we present a fully automated procedure for turbine blade optimisation. Optimisation... more In this paper we present a fully automated procedure for turbine blade optimisation. Optimisation process consists of geometry parametrisation using B-splines, mesh deformation using the dynamic mesh library in OpenFOAM, numerical simulation of transonic flow through the blade passage and finding the feasible solutions with the Multi-Objective Genetic Algorithm (MOGA). The process proved to be robust whether starting the optimisation from unfeasible geometry or a conventional blade profile.
In this thesis a comparison of pressure–velocity coupling algorithms is conducted with special em... more In this thesis a comparison of pressure–velocity coupling algorithms is conducted with special emphasis on the implicit coupling of momentum and pr
This chapter covers the fundamental aspects of Computational Fluid Dynamics simulation tools and ... more This chapter covers the fundamental aspects of Computational Fluid Dynamics simulation tools and introduces the terminology and principles of the second order accurate Finite Volume Method with polyhedral mesh support, as implemented in OpenFOAM (Weller et al. 1998). The first part is dedicated to types and properties of computational meshes, followed by a description of the Finite Volume discretisation for a generic scalar transport equation. Algorithms for pressure-velocity coupling for single–phase incompressible Newtonian fluid flow, as described by the Navier-Stokes equations are presented, supported by an overview of algorithms for the solution of the resulting linear system of algebraic equations. Application of the polyhedral FVM solver for real engineering problems is illustrated on some practical examples.
Centrifugalne ili radijalne pumpe su podskupina dinamickih turbopumpi. Služe za podizanje energet... more Centrifugalne ili radijalne pumpe su podskupina dinamickih turbopumpi. Služe za podizanje energetske razine fluida u cilju postizanja određenog protoka ili visine dobave. Visina dobave pumpe trosi se na savladavanje geodetske visine između razina u spremnicima i visine gubitaka u cjevovodima. Radna tocka pumpe je ravnotežno stanje energije koju pumpa predaje radnom fluidu i energije koju trosi sustav na savladavanje geodetske visine i hidrodinamickih otpora. Prakticno, radna tocka nalazi se u sjecistu karakteristike sustava (cjevovoda) na kojeg je pumpa prikljucena i karakteristike pumpe prikazanima u dijagramu visina dobave-protok (Q-H dijagramu). U ovome radu prikazana je simulacija strujanja fluida u dvije razlicite konstrukcije centrifugalnih pumpi. Za simulacije su koristeni spregnuti i odvojeni rjesavac za nestlaciva strujanja iz paketa otvorenog koda OpenFOAM. Uspoređena je konvergencija rjesavaca za polja brzine i tlaka te za visinu dobave pumpe. Radne tocke dobivene simulac...
Optimizacija je disciplina numericke matematike za unaprijeđivanje rada sustava ili procesa da bi... more Optimizacija je disciplina numericke matematike za unaprijeđivanje rada sustava ili procesa da bi rezultati bili najbolji moguci. Optimizacijski algoritmi za zadacu imaju minimizaciju ili maksimizaciju funkcije cilja koja se proracunava simulacijom, uz odgovarajuca ogranicenja varijabli. U radu su opisani parametri i postavke optimizacije po visestrukim funkcijama cilja sa ogranicenjima varijabli cijevnog izmjenjivaca topline. Traže se optimalne pozicije cijevi kako bi se povecao prirast temperature fluida uz sto manji pad tlaka u izmjenjivacu. temperaturni prirast i pad tlaka su ujedno i funkcije cilja za ovaj problem. Za optimizaciju su koristena tri racunalna alata: open source alat Salome za konstrukciju geometrije, open source paket za racunalnu dinamiku fluida OpenFOAM i open source software za optimizaciju Dakota. Ispitivani su razliciti parametri genetskog algoritma za optimizaciju po visestrukim funkcijama cilja te su rezultati prikazani preko Pareto linija. Provedena je i ...
An automated process for turbine blade optimisation coupled with CFD is presented in this study. ... more An automated process for turbine blade optimisation coupled with CFD is presented in this study. A large number of turbine blade shapes is considered in the optimisation process, thus a large number of corresponding computational meshes would have to be used for CFD calculations. It has been well documented that local mesh resolution and mesh quality is one of principal sources of discretisation error in CFD. For consistent results in optimisation studies it is essential to control the absolute value and distribution of mesh- induced errors, ideally by employing a family of self-similar meshes. This is not easily achieved where the automated optimisation loop involves the use of an external or automatic mesh generator. In this study, a procedure of geometry variation in the CFD mesh is performed using a mesh morphing procedure, where the existing mesh will be automatically deformed to accommodate boundary deformation. Mesh morphing not only simplifies the optimisation loop but also ...
CFD simulation results for self propelled full scale ship are compared to sea trial measurements ... more CFD simulation results for self propelled full scale ship are compared to sea trial measurements in this work. Two–phase RANS based CFD numerical model used in this work is based on the Ghost Fluid Method for numerically robust treatment of discontinuities at the free surface and the algebraic Volume–of–Fluid method for interface capturing. The propeller is modelled as a pressure–jump based actuator disc, allowing CPU time efficient simulations while preserving the accuracy of integral results. The numerical model is implemented in foam–extend, a community driven fork of the OpenFOAM software. The comparison with sea trials includes achieved forward speed, thrust and torque for given shaft speed (in RPM) for a general cargo carrier.
This paper presents the performance of the implicitly coupled pressure-velocity solver for severa... more This paper presents the performance of the implicitly coupled pressure-velocity solver for several car aerodynamics cases: flow around a bluff body with a diffuser section, rotating wheel, generic car and Formula 1 front wing.
Strucne analize pokazuju da Republika Hrvatska raspolaže velikim energetskim resursima biomase iz... more Strucne analize pokazuju da Republika Hrvatska raspolaže velikim energetskim resursima biomase iz poljoprivrede, vocarstva i sumarstva. Buduci da se vise od 50% ovih resursa nalazi u ravnicarskom dijelu, a nesto manje u brdskim dijelovima, moguce je gradnjom malih kogeneracijskih elektrana na biomasu zadovoljiti veliki dio vlastitih potreba lokalnih zajednica za elektricnom i toplinskom energijom. Studije isplativosti su pokazale da je optimalna elektricna snaga termoelektrane 1 do 2 MW i oko 4 do 8 MW toplinske snage. U okviru rada predložena je toplinska shema jedne takve kogeneracijske termoelektrane, a na temelju potrebne elektricne snage izracunat je potrebni maseni protok pare na ulazu u turbinu. Prikazan je termodinamicki i aerodinamicki proracun turbine, odabrani su profili lopatica te izracunati gubici svih stupnjeva te snaga turbine.
Turbomachinery CFD has been extensively used for decades and variety of tools have been developed... more Turbomachinery CFD has been extensively used for decades and variety of tools have been developed for dealing with specific phenomena appearing in these machines. The tools enable significant computational savings, or provide simplified models for preliminary evaluation, which resulted in establishing CFD as a common, efficient R&D technique in industry. In this paper we present the methods for modeling complex flows inside various types of turbomachinery. A general overview of tools for turbomachinery simulations available in foam-extend is given, with the application demonstrated for both incompressible and compressible flow problems. Appropriate methods should be chosen depending on the physics and geometry involved: • steady-state or transient approach, • single blade passage or full annulus configuration, • type of rotor-stator interaction interface, • compressible or incompressible problem, • implicitly block–coupled or segregated pressure-velocity system, etc. All options wil...
In this paper we present a fully automated procedure for turbine blade optimisation. Optimisation... more In this paper we present a fully automated procedure for turbine blade optimisation. Optimisation process consists of geometry parametrisation using B-splines, mesh deformation using the dynamic mesh library in OpenFOAM, numerical simulation of transonic flow through the blade passage and finding the feasible solutions with the Multi-Objective Genetic Algorithm (MOGA). The process proved to be robust whether starting the optimisation from unfeasible geometry or a conventional blade profile.
In this thesis a comparison of pressure–velocity coupling algorithms is conducted with special em... more In this thesis a comparison of pressure–velocity coupling algorithms is conducted with special emphasis on the implicit coupling of momentum and pr
This chapter covers the fundamental aspects of Computational Fluid Dynamics simulation tools and ... more This chapter covers the fundamental aspects of Computational Fluid Dynamics simulation tools and introduces the terminology and principles of the second order accurate Finite Volume Method with polyhedral mesh support, as implemented in OpenFOAM (Weller et al. 1998). The first part is dedicated to types and properties of computational meshes, followed by a description of the Finite Volume discretisation for a generic scalar transport equation. Algorithms for pressure-velocity coupling for single–phase incompressible Newtonian fluid flow, as described by the Navier-Stokes equations are presented, supported by an overview of algorithms for the solution of the resulting linear system of algebraic equations. Application of the polyhedral FVM solver for real engineering problems is illustrated on some practical examples.
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