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H.N. Michael

Bio: H.N. Michael is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 397 citations.


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Journal ArticleDOI
TL;DR: This paper reviews the current state of the art CFD for analysis of blood pumps, including a practical critical review of the studies to date, which should help device designers choose the most appropriate methods; a summary of blood damage models and the difficulties in implementing them into CFD; and current gaps in knowledge and areas for future work.

219 citations

Book
01 Nov 1994
TL;DR: In this paper, a conception reference record was created on 2005-11-18, modified on 2016-08-08 and was used for the construction of the turbines of the turbine.
Abstract: Keywords: compresseurs ; turbines ; conception Reference Record created on 2005-11-18, modified on 2016-08-08

214 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the state-of-the-art of pump running in turbine mode for low capacity power generation in micro-hydropower plants as well as in water supply piping systems is presented.
Abstract: In remote communities where it is not economical and practically possible to take the grid connection, stand-alone small hydro systems can be used to fulfill the energy requirement Small-scale hydroelectric power systems are emerging as a promising source of renewable energy generation, but they require low cost hydraulic and electric equipments to make them economically feasible In such plants, pumps can be used in turbine mode considering various advantages associated with pump eg ease of availability, proven technology, low initial and maintenance cost, availability for a wide range of heads and flows, etc The efficiency of pump as turbine (PAT) is usually lower than that of conventional hydro turbines However, efficiency is not the primary selection criterion for such machines and it is recommended to operate such machines around maximum efficiency point In the present study, different turbines suitable for micro-hydropower plants are discussed The historical development of PAT is described The review of the state-of-the-art of pump running in turbine mode is presented Different pumps suitable to run in turbine mode for low capacity power generation in micro-hydropower plants as well as in water supply piping systems are discussed Theoretical, experimental and numerical investigations carried out by different researchers on PAT are reviewed The research work on PAT including criteria for selection of pump running as turbine, cavitation analysis, force analysis, loss distribution, various methods of performance enhancement, cost analysis of hydropower plant with conventional hydro turbine and PAT, applications of PAT in water supply pipelines, etc is discussed The worldwide implementation of PAT and different manufacturers of PAT are described The limitations in implementation of PAT as well as the recommendations to improve the performance of PAT are described The current trends and future scope for the further improvement and implementation of PAT are also discussed

182 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the subgrid scales has been modeled through a localized dynamic Smagorinsky model implemented in the commercial CFD code FINE/Turbo, and a detailed analysis of the results of LES at design load, Q =Q d, and severe off-design conditions, at quarter-load Q=0.25Q d, is presented.
Abstract: The flow field in a shrouded six-bladed centrifugal pump impeller has been investigated using large eddy simulation (LES). The effect of the subgrid scales has been modeled through a localized dynamic Smagorinsky model implemented in the commercial CFD code FINE/Turbo. A detailed analysis of the results of LES at design load, Q =Q d , and severe off-design conditions, at quarter-load Q=0.25Q d , is presented. At design load LES reveals a well-behaved flow field with no significant separation. At quarter-load significant differences between adjacent impeller passages are revealed. A steady nonrotating stall phenomenon is observed in the entrance of one passage and a relative eddy develops in the remaining part of the passage. The stall unblocks the adjacent passage which exhibits a flow dominated by rotational effects. Velocities predicted by LES and steady-state Reynolds averaged Navier-Stokes (RANS) simulations based on the Baldwin-Lomax and Chien k-e turbulence models are compared with experimental data obtained from particle image velocimetry (PIV)

181 citations

Journal ArticleDOI
TL;DR: In this paper, a design procedure that couples a parallel hydraulic circuit with an overall plant efficiency criteria for the market pump selection within a water distribution network (WDNs) is proposed. And computational fluid dynamics (CFD) is shown as a suitable alternative for performance curve assessment covering the limited number of experimental data.
Abstract: Pump operating as turbine (PAT) is an effective source of reducing the equipment cost in small hydropower plants. However, the manufacturers provide poor information on the PAT performance thus representing a limit for its wider diffusion. Additional implementation difficulties arise under variable operating con- ditions, characteristic of water distribution networks (WDNs). WDNs allow to obtain widespread and globally significant amount of produced energy by exploiting the head drop due to the network pressure control strategy for leak reductions. Thus a design procedure is proposed that couples a parallel hydraulic circuit with an overall plant efficiency criteria for the market pump selection within a WDN. The proposed design method allows to identify the performance curves of the PAT that maximizes the produced energy for an assigned flow and pressure-head distribution pattern. Finally, computational fluid dynamics (CFD) is shown as a suitable alternative for performance curve assessment covering the limited number of experimental data.

177 citations