International Journal of Turbomachinery, Propulsion and Power最新文献

{"title":"Effect of the von Karman Shedding Frequency on the Hydrodynamics of a Francis Turbine Operating at Nominal Load","authors":"Giacomo Zanetti, G. Cavazzini, A. Santolin","doi":"10.3390/ijtpp8030027","DOIUrl":"https://doi.org/10.3390/ijtpp8030027","url":null,"abstract":"This paper presents a numerical analysis of the influence of the von Karman vortex shedding at the blade trailing edge on the hydrodynamics of a recently installed small hydro Francis turbine manifesting very loud and high-frequency acoustic pulsations when operating close to the nominal load. A reduced single-passage numerical model is developed to reduce the computational effort of the simulation while ensuring high accuracy in the assessment of fluid flow. The accuracy of the proposed numerical approach is investigated by comparing the frequency spectrum of the experimentally acquired acoustic frequency and the numerical pressure signals, confirming the nature of the machine’s vibrations. The validated numerical model represents a useful tool for an in-depth analysis of the machine’s hydrodynamics in the preliminary design phases. The proposed approach represents a valid alternative to the traditional correlation-based approach for the evaluation of the von Karman shedding frequency with less computational effort compared with a transient simulation of the entire machine.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42318575","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":"Heat Transfer Analysis of Damaged Shrouded High-Pressure Turbine Rotor Blades","authors":"Mario Carta, T. Ghisu, S. Shahpar","doi":"10.3390/ijtpp8030024","DOIUrl":"https://doi.org/10.3390/ijtpp8030024","url":null,"abstract":"Due to the increasingly high turbine inlet temperatures, heat transfer analysis is now, more than ever, a vital part of the design and optimization of high-pressure turbine rotor blades of a modern jet engine. The present study aimed to find out how shape deviation and in-service deterioration affect heat exchange patterns on the rotor blade. The rotor geometries used for this analysis are represented by a set of high-resolution 3D structured light scans of blades with the same number of in-service hours. An automatic meshing technique was employed to generate high-resolution meshes directly on the scanned rotor geometries, which captured all the surface features with high fidelity. Steady-state 3D RANS flow simulations with a k-ω SST turbulence model were conducted on a one-and-a-half stage computational domain of the scanned geometries. First, the distribution of the heat transfer coefficient was calculated for each blade; then, a correlation was sought between the heat transfer coefficient and parametrized shape deviation, to assess the impact of each parameter on HTC levels.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43867520","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":"Rotor Cascade Assessment at Off-Design Condition: An Aerodynamic Investigation on Platform Cooling","authors":"H. Abdeh, G. Barigozzi, N. Franchina","doi":"10.3390/ijtpp8030023","DOIUrl":"https://doi.org/10.3390/ijtpp8030023","url":null,"abstract":"Off-design condition of a rotor blade cascade with and without platform cooling was experimentally investigated. The ability of the gas turbine to operate down to 50% to 20% of its nominal intake air flow rate has an important consequence in the change in the inlet incidence angle, which varied from nominal to −20°. Platform cooling through an upstream slot simulating the stator-to-rotor interface gap was considered. The impact of rotation on purge flow injection was simulated by installing fins inside the slot to give the coolant flow a tangential direction. Aerodynamic measurements to quantify the cascade aerodynamic loss and secondary flow structures were performed at Ma2is = 0.55, varying the coolant to main flow mass flow ratio (MFR%) and the incidence angle. The results show that losses strongly increase with MFR. A negative incidence allows a reduction in the overall loss even when coolant is injected with a high MFR. The more negative the incidence, the greater the loss reduction.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44910037","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":"Experimental Analysis of the Three Dimensional Flow in a Wells Turbine Rotor","authors":"F. Licheri, T. Ghisu, F. Cambuli, P. Puddu","doi":"10.3390/ijtpp8030021","DOIUrl":"https://doi.org/10.3390/ijtpp8030021","url":null,"abstract":"An experimental investigation of the local flow field in a Wells turbine has been conducted, in order to produce a detailed analysis of the aerodynamic characteristics of the rotor and support the search for optimized solutions. The measurements were conducted with a hot-wire anemometer (HWA) probe, reconstructing the local three-dimensional flow field both upstream and downstream of a small-scale Wells turbine. The multi-rotation technique has been applied to measure the three velocity components of the flow field for a fixed operating condition. The results of the investigation show the local flow structures along a blade pitch, highlighting the location and radial extension of the vortices which interact with the clean flow, thus degrading the turbine’s overall performance. Some peculiarities of this turbine have also been shown, and need to be considered in order to propose modified solutions to improve its performance.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42997244","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":"Aerodynamics and Sealing Performance of the Downstream Hub Rim Seal in a High-Pressure Turbine Stage","authors":"F. Merli, Nicolas Krajnc, Asim Hafizovic, M. Patinios, E. Göttlich","doi":"10.3390/ijtpp8030020","DOIUrl":"https://doi.org/10.3390/ijtpp8030020","url":null,"abstract":"The purpose of the paper is to characterize the aerodynamic behavior of a rotor-downstream hub cavity rim seal in a high-pressure turbine (HPT) stage. The experimental data are acquired in the Transonic Test Turbine Facility at the Graz University of Technology: the test setup includes two engine-representative turbine stages (the last HPT stage and first LPT stage), with the intermediate turbine duct in between. All stator-rotor cavities are supplied with purge flows by a secondary air system, which simulates the bleeding air from the compressor stages of the real engine. The HPT downstream hub cavity is provided with wall taps and pitot tubes at different radial and circumferential locations, which allows the performance of steady pressure and seed gas concentration measurements for different purge mass flows and HPT vanes clocking positions. Moreover, miniaturized pressure transducers are adopted to evaluate the unsteady pressure distribution, and an oil flow visualization is performed to retrieve additional information on the wheel space structures. The annulus pressure asymmetry depends on the HPT vane clocking, but this is shown to have negligible impact on the minimum purge mass flow required to seal the cavity. However, the hub pressure profile drives the distribution of the cavity egress in the turbine channel. The unsteady pressure field is dominated by blade-synchronous oscillations. No non-synchronous components with comparable intensity are detected.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45585435","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":"Advanced Gas Turbine Cooling for the Carbon-Neutral Era","authors":"K. Takeishi, Robert Krewinkel","doi":"10.3390/ijtpp8030019","DOIUrl":"https://doi.org/10.3390/ijtpp8030019","url":null,"abstract":"In the coming carbon-neutral era, industrial gas turbines (GT) will continue to play an important role as energy conversion equipment with high thermal efficiency and as stabilizers of the electric power grid. Because of the transition to a clean fuel, such as hydrogen or ammonia, the main modifications will lie with the combustor. It can be expected that small and medium-sized gas turbines will burn fewer inferior fuels, and the scope of cogeneration activities they are used for will be expanded. Industrial gas turbine cycles including CCGT appropriate for the carbon-neutral era are surveyed from the viewpoint of thermodynamics. The use of clean fuels and carbon capture and storage (CCS) will inevitably increase the unit cost of power generation. Therefore, the first objective is to present thermodynamic cycles that fulfil these requirements, as well as their verification tests. One conclusion is that it is necessary to realize the oxy-fuel cycle as a method to utilize carbon-heavy fuels and biomass and not generate NOx from hydrogen combustion at high temperatures. The second objective of the authors is to show the required morphology of the cooling structures in airfoils, which enable industrial gas turbines with a higher efficiency. In order to achieve this, a survey of the historical development of the existing cooling methods is presented first. CastCool® and wafer and diffusion bonding blades are discussed as turbine cooling technologies applicable to future GTs. Based on these, new designs already under development are shown. Most of the impetus comes from the development of aviation airfoils, which can be more readily applied to industrial gas turbines because the operation will become more similar. Double-wall cooling (DWC) blades can be considered for these future industrial gas turbines. It will be possible in the near future to fabricate the DWC structures desired by turbine cooling designers using additive manufacturing (AM). Another conclusion is that additively manufactured DWC is the best cooling technique for these future gas turbines. However, at present, research in this field and the data generated are scattered, and it is not yet possible for heat transfer designers to fabricate cooling structures with the desired accuracy.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48677089","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":"Development of Sewage Pumps with Numerical and Experimental Support","authors":"D. Beck, P. Thamsen","doi":"10.3390/ijtpp8020018","DOIUrl":"https://doi.org/10.3390/ijtpp8020018","url":null,"abstract":"Especially in the field of sewage pumps, the design of radial impellers focuses not only on maximum efficiency but also on functionality in terms of susceptibility to clogging by fibrous media. In general, the efficiency of sewage impellers is significantly lower than that of clear water impellers. These sewage impellers are designed with a low number of blades to ensure that fibrous media can be pumped. This paper describes the methodology of an optimisation for a sewage impeller. The optimisation is carried out on a semi-open two-channel impeller as an example. Therefore, a new impeller is designed for a given volute casing. Based on a basic design for given boundary conditions, the impeller is verified by means of numerical simulation. The manufactured impeller is then tested on the test rig to verify the simulation. With regard to the optical investigations, the clogging behaviour of the impeller is specifically improved over three different modifications in order to finally present an impeller with good efficiency and a low clogging tendency.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44214339","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":"State of the Art on Two-Phase Non-Miscible Liquid/Gas Flow Transport Analysis in Radial Centrifugal Pumps-Part A: General Considerations on Two-Phase Liquid/Gas Flows in Centrifugal Pumps","authors":"G. Bois","doi":"10.3390/ijtpp8020016","DOIUrl":"https://doi.org/10.3390/ijtpp8020016","url":null,"abstract":"Gas–liquid mixtures are present in numerous industrial applications, such as in the process industry, oil production and transport with natural gas, deep-sea extraction, and irrigation. Any pump may have to carry multiphase flows. However, the present document is related to non-miscible liquid/gas flow transport analysis in centrifugal pumps because which topic can be a more challenging task compared with axial and mixed flow machines due to specific body force and buoyancy actions and large density differences between the phases. The present document first introduces the main usual gas–liquid two-phase definitions and simplifications. A dimensional analysis introduces the main flow variables and parameters that are used for pumps. Basic physical aspects of flow motion in an impeller channel are explained, and a rapid description of two-phase flow patterns in radial flow pumps is described. Finally, a review of simplified empirical and semi-empirical analytical models is proposed with their limitations.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70120772","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":"Numerical Analysis of the Flow by Using a Free Runner Downstream the Francis Turbine","authors":"A. Bosioc, R. Szakal, A. Stuparu, R. Susan-Resiga","doi":"10.3390/ijtpp8020014","DOIUrl":"https://doi.org/10.3390/ijtpp8020014","url":null,"abstract":"The current requirements of industrialized countries require the use of as much renewable energy as possible. One significant problem with renewable energy is that the produced power fluctuates. Currently, the only method available for energy compensation in the shortest time is given by hydroelectric power plants. Instead, hydroelectric power plants (especially the plants equipped with hydraulic turbines with fixed blades) are designed to operate in the vicinity of the optimal operating point with a maximum ±10% deviation. The energy market requires that hydraulic turbines operate in an increasingly wide area between −35% to 20% from the optimum operating point. Operation of hydraulic turbines far from the optimum operating point involves the appearance downstream of the turbine of a decelerated swirling flow with hydraulic instabilities (known in the literature as the vortex rope). The main purpose of this paper is to investigate numerically a new concept by using a free runner downstream on the main hydraulic runner turbine more precisely in the draft tube cone. The free runner concept requires rotations at the runaway speed with vanishing mechanical torque. The main purpose is to redistribute the total pressure and the moment between the shaft and the periphery. In addition, the free runner does not modify the operating point of the main hydraulic turbine runner.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42865806","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":"State of the Art on Two-Phase Non-Miscible Liquid/Gas Flow Transport Analysis in Radial Centrifugal Pumps Part C: CFD Approaches with Emphasis on Improved Models","authors":"Markus Hundshagen, R. Skoda","doi":"10.3390/ijtpp8020015","DOIUrl":"https://doi.org/10.3390/ijtpp8020015","url":null,"abstract":"Predicting pump performance and ensuring operational reliability under two-phase conditions is a major goal of three-dimensional (3D) computational fluid dynamics (CFD) analysis of liquid/gas radial centrifugal pump flows. Hence, 3D CFD methods are increasingly applied to such flows in academia and industry. The CFD analysis of liquid/gas pump flows demands careful selection of sub-models from several fields in CFD, such as two-phase and turbulence modeling, as well as high-quality meshing of complex geometries. This paper presents an overview of current CFD simulation strategies, and recent progress in two-phase modeling is outlined. Particular focus is given to different approaches for dispersed bubbly flow and coherent gas accumulations. For dispersed bubbly flow regions, Euler–Euler Two-Fluid models are discussed, including population balance and bubble interaction models. For coherent gas pocket flow, essentially interface-capturing Volume-of-Fluid methods are applied. A hybrid model is suggested, i.e., a combination of an Euler–Euler Two-Fluid model with interface-capturing properties, predicting bubbly flow regimes as well as regimes with coherent gas pockets. The importance of considering scale-resolving turbulence models for highly-unsteady two-phase flow regions is emphasized.","PeriodicalId":36626,"journal":{"name":"International Journal of Turbomachinery, Propulsion and Power","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47919090","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}