The present paper focuses on an enhancement of the Master Cycle. In the first part, the paper presents a classical Master Cycle which is a modification of the double reheat Rankine cycle. This modification allows to slightly increase efficiency, resolves problems caused by superheated steam on bleeds and decreases mass flow rate of steam directed to reheat. These improvements include the implementation of a tuning turbine from which a few bleeds are taken. In the proposed Enhanced Master Cycle all bleeds are placed on the tuning turbine. This alteration results in an increased efficiency, further reduction of steam mass flow on reheats and simplification of low pressure turbine. Comparative calculations of the double reheat cycle, Master Cycle and Enhanced Master Cycle are presented. Cycles operate on the advanced ultra-supercritical parameters. The Enhanced Master Cycle achieved the highest net efficiency 54.64% and required the lowest steam mass flow on superheaters.
{"title":"ENHANCED MASTER CYCLE - SIGNIFICANT IMPROVEMENT OF STEAM RANKINE CYCLE","authors":"S. Głuch, M. Piwowarski","doi":"10.21495/71-0-125","DOIUrl":"https://doi.org/10.21495/71-0-125","url":null,"abstract":"The present paper focuses on an enhancement of the Master Cycle. In the first part, the paper presents a classical Master Cycle which is a modification of the double reheat Rankine cycle. This modification allows to slightly increase efficiency, resolves problems caused by superheated steam on bleeds and decreases mass flow rate of steam directed to reheat. These improvements include the implementation of a tuning turbine from which a few bleeds are taken. In the proposed Enhanced Master Cycle all bleeds are placed on the tuning turbine. This alteration results in an increased efficiency, further reduction of steam mass flow on reheats and simplification of low pressure turbine. Comparative calculations of the double reheat cycle, Master Cycle and Enhanced Master Cycle are presented. Cycles operate on the advanced ultra-supercritical parameters. The Enhanced Master Cycle achieved the highest net efficiency 54.64% and required the lowest steam mass flow on superheaters.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124963743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Gabriel, J. Masák, J. Plešek, L. Kloc, P. Dymáček
: A complex creep constitutive model including transient effects was implemented in the finite element code PMD (Package for Machine Design). The material model for P-91-type creep-resistant steel together with computer implementation was verified by means of uniaxial stress loadings. Testing bar was discretized by the finite element method (FEM) and loaded with uniaxial stresses and constant temperatures that were used to demonstrate the analytical solutions in original paper.
在有限元程序PMD (Package for Machine Design)中实现了包含瞬态效应的复杂蠕变本构模型。采用单轴应力加载方法对p- 91型抗蠕变钢材料模型进行了验证，并进行了计算机仿真。采用有限元法对试验杆进行离散化，并施加单轴应力和恒温载荷，验证了本文的解析解。
{"title":"FINITE ELEMENT IMPLEMENTATION OF CREEP CONSTITUTIVE MODEL INCLUDING TRANSIENT EFFECTS","authors":"D. Gabriel, J. Masák, J. Plešek, L. Kloc, P. Dymáček","doi":"10.21495/71-0-121","DOIUrl":"https://doi.org/10.21495/71-0-121","url":null,"abstract":": A complex creep constitutive model including transient effects was implemented in the finite element code PMD (Package for Machine Design). The material model for P-91-type creep-resistant steel together with computer implementation was verified by means of uniaxial stress loadings. Testing bar was discretized by the finite element method (FEM) and loaded with uniaxial stresses and constant temperatures that were used to demonstrate the analytical solutions in original paper.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122787497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"THE SETTING OF CFD MODEL WITH MAGNETORHEOLOGICAL FLUID AND ITS INFLUENCE ON THE RESULTS","authors":"M. Kubík, J. Roupec, F. Jeniš, I. Mazůrek","doi":"10.21495/71-0-223","DOIUrl":"https://doi.org/10.21495/71-0-223","url":null,"abstract":"","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123202371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: In this paper the design and stress analysis of a frame with suspension used in Modernity terrain rover is presented. The mentioned rover was used in University Rover Challenge 2018 (Utah, USA) and finished the challenge in the first place. The results presented in this paper are achieved with the SolidWorks software. The simulations are concern on maximum stress and displacements distributions and are done for different cases such as standby mode and wheel-rock collision.
{"title":"DESIGN AND STRESS ANALYSIS OF A FRAME WITH SUSPENSION TO MULTITASK TERRAIN ROVER","authors":"M. Pierzgalski, K. Sokół, D. Cekus","doi":"10.21495/71-0-283","DOIUrl":"https://doi.org/10.21495/71-0-283","url":null,"abstract":": In this paper the design and stress analysis of a frame with suspension used in Modernity terrain rover is presented. The mentioned rover was used in University Rover Challenge 2018 (Utah, USA) and finished the challenge in the first place. The results presented in this paper are achieved with the SolidWorks software. The simulations are concern on maximum stress and displacements distributions and are done for different cases such as standby mode and wheel-rock collision.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127568069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Small unmanned aerial vehicles (SUAVs) typically rely on a fixed pitch propeller to produce required thrust. Knowledge of the propeller performance characteristics can help to properly choose or design an optimal propeller for a given SUAV and its mission. These characteristics can be obtained by a number of methods, with this paper focusing on the so-called blade element Joukowsky model (BEM). The original model was derived for the propeller operating in an axial flow. This paper explains a modified version of the original algorithm to introduce a non-zero incident angle to the calculation. Furthermore, it presents results from the measurement of the Bambula 18x8 fixed pitch propeller in an incident flow and compares the results from the measurement with the calculated data.
{"title":"IMPACT OF NON-ZERO INCIDENT ANGLE TO PROPELLER PERFORMANCE CHARACTERISTICS AND ITS BEM MODEL","authors":"J. Hnidka, D. Rozehnal, V. B. Nguyen","doi":"10.21495/71-0-149","DOIUrl":"https://doi.org/10.21495/71-0-149","url":null,"abstract":": Small unmanned aerial vehicles (SUAVs) typically rely on a fixed pitch propeller to produce required thrust. Knowledge of the propeller performance characteristics can help to properly choose or design an optimal propeller for a given SUAV and its mission. These characteristics can be obtained by a number of methods, with this paper focusing on the so-called blade element Joukowsky model (BEM). The original model was derived for the propeller operating in an axial flow. This paper explains a modified version of the original algorithm to introduce a non-zero incident angle to the calculation. Furthermore, it presents results from the measurement of the Bambula 18x8 fixed pitch propeller in an incident flow and compares the results from the measurement with the calculated data.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128788926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: The paper presents a calculation model of heat exchange in the body of a refrigerated truck supplied from a cold reservoir. On the basis of this model, the temperature inside the body was simulated, taking into account: changes in ambient temperature during a hot day, changes in solar irradiance, loss of load, distributed during the running of the vehicle. In the era of energy savings, this solution - compared to traditional solutions in this area - allows for rational management of the energy needed to supply the car body. The MATLAB Simulink software package was used for modeling.
{"title":"MODELLING OF TEMPERATURES IN REFRIGERATED TRUCK BODY SUPPLIED FROM HEAT RESERVOIR","authors":"S. Kwasniowski, S. Haładyn","doi":"10.21495/71-0-227","DOIUrl":"https://doi.org/10.21495/71-0-227","url":null,"abstract":": The paper presents a calculation model of heat exchange in the body of a refrigerated truck supplied from a cold reservoir. On the basis of this model, the temperature inside the body was simulated, taking into account: changes in ambient temperature during a hot day, changes in solar irradiance, loss of load, distributed during the running of the vehicle. In the era of energy savings, this solution - compared to traditional solutions in this area - allows for rational management of the energy needed to supply the car body. The MATLAB Simulink software package was used for modeling.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128567510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The flow around an airfoil is analyzed from the point of view turbulence anisotropy assessment. The turbulent flow-field in the vicinity of an airfoil is populated by vortices, in some locations they tend to regularity in orientation, i.e. to anisotropy. However in the wake behind the plate as well as in the core of the boundary layer on the plate suction side the turbulence is close to isotropic state.
{"title":"ANISOTROPY OF TURBULENT FLOW AROUND AN AIRFOIL","authors":"V. Uruba, P. Procházka, V. Skála","doi":"10.21495/71-0-379","DOIUrl":"https://doi.org/10.21495/71-0-379","url":null,"abstract":"The flow around an airfoil is analyzed from the point of view turbulence anisotropy assessment. The turbulent flow-field in the vicinity of an airfoil is populated by vortices, in some locations they tend to regularity in orientation, i.e. to anisotropy. However in the wake behind the plate as well as in the core of the boundary layer on the plate suction side the turbulence is close to isotropic state.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114260507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Friction Stir Welding (FSW) is one of the most effective solid state joining processes and has numerous potential applications in many industries. The aim of this paper is to describe the thermal-fluid and mechanical simulation of FSW using the finite element method in program SYSWELD. The simulation of FSW process requires the modelling of the complex interaction between thermal, metallurgical and mechanical phenomena. Thermal-mechanical results from the numerical simulation using SYSWELD are here presented for aluminium alloy.
{"title":"NUMERICAL SIMULATION OF FRICTION STIR WELDING OF ALUMINIUM PLATE","authors":"R. Janco, P. Élesztős, L. Écsi, P. Šlesar","doi":"10.21495/71-0-161","DOIUrl":"https://doi.org/10.21495/71-0-161","url":null,"abstract":"Friction Stir Welding (FSW) is one of the most effective solid state joining processes and has numerous potential applications in many industries. The aim of this paper is to describe the thermal-fluid and mechanical simulation of FSW using the finite element method in program SYSWELD. The simulation of FSW process requires the modelling of the complex interaction between thermal, metallurgical and mechanical phenomena. Thermal-mechanical results from the numerical simulation using SYSWELD are here presented for aluminium alloy.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124964355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Horáček, V. Radolf, V. Bula, P. Šidlof, A. Geneid, A. Laukkanen
This preliminary study shows that the impact stress between the colliding vocal folds during phonation should not be evaluated from the maximum velocity of the glottal closing because the velocity of the closing diminishes just before the glottal closure. This phenomenon, which can be caused by a pressure cushion effect in the fast narrowing glottal gap, is demonstrated with measurements from high speed camera images recorded from human and on a physical laboratory model for vowel [u:] phonation and on a threemass computer model employing a Hertz model of impact force. For a more detailed future study of this phenomenon a faster camera has to be used.
{"title":"EXPERIMENTAL AND COMPUTER MODELLING STUDY OF GLOTTAL CLOSING VELOCITY DURING PHONATION","authors":"J. Horáček, V. Radolf, V. Bula, P. Šidlof, A. Geneid, A. Laukkanen","doi":"10.21495/71-0-153","DOIUrl":"https://doi.org/10.21495/71-0-153","url":null,"abstract":"This preliminary study shows that the impact stress between the colliding vocal folds during phonation should not be evaluated from the maximum velocity of the glottal closing because the velocity of the closing diminishes just before the glottal closure. This phenomenon, which can be caused by a pressure cushion effect in the fast narrowing glottal gap, is demonstrated with measurements from high speed camera images recorded from human and on a physical laboratory model for vowel [u:] phonation and on a threemass computer model employing a Hertz model of impact force. For a more detailed future study of this phenomenon a faster camera has to be used.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114939783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The presented paper describes the dynamic analyses of a newly designed experimental stand for testing of turbine wheels. The experimental device includes two overhung rotor discs attached to two coaxial shafts. The main focus is paid on the rotor dynamic analysis, i.e. the complex modes analysis including shafts rotation. The evaluated parameters include rotor revolutions and stiffness parameters of bearings. The evaluated results include characteristics of complex modes and identification of whirl resonances and critical speeds of the system.
{"title":"DYNAMIC ANALYSIS OF TWO-STAGE TURBINE EXPERIMENTAL STAND","authors":"J. Cecrdle, O. Vích","doi":"10.21495/71-0-85","DOIUrl":"https://doi.org/10.21495/71-0-85","url":null,"abstract":"The presented paper describes the dynamic analyses of a newly designed experimental stand for testing of turbine wheels. The experimental device includes two overhung rotor discs attached to two coaxial shafts. The main focus is paid on the rotor dynamic analysis, i.e. the complex modes analysis including shafts rotation. The evaluated parameters include rotor revolutions and stiffness parameters of bearings. The evaluated results include characteristics of complex modes and identification of whirl resonances and critical speeds of the system.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131403885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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