Abstract

Stringent environmental constraints are usually associated with or applied to the siting and installation of new pipeline facilities. This has resulted in a significant portion of the design effort and ultimate cost of the facility to be dedicated to the mitigation of these environmental concerns. This paper describes how a compressor station can be designed and built such that stringent silencing requirements can be satisfied. The paper also references specific aspects of design which were successfully applied to the Parkway Compressor Station, Canada.Copyright © 1991 by ASME

Abstract

This paper describes and discusses techniques which can effectively diagnose dynamics problems in turbomachinery. A variety of elusive dynamics problems are identified which require definition, quantification, diagnosis, and monitoring. The state of the art in measurement and signal processing techniques is discussed with reference to such factors as the directness of the measurement, the degree of intrusion required, the difficulty of installation, and the reliability or durability of the sensor. Several examples of techniques are provided which have proved to be effective in diagnosing elusive dynamics problems; some examples allow comparison of alternative techniques with different degrees of effectiveness. Problems addressed include rotating stall in the compressor section of a gas turbine, coupled lateral/torsional vibration in a gas turbine driven pipeline compressor, forced vibration of combustor parts, strain gage telemetry of blade vibrations, and nonintrusive measurement of blade vibrations using bearing mounted accelerometers.Copyright © 1989 by ASME

Abstract

Flow-accelerated corrosion (FAC) wear is the complex mechanism of damage of elements of NPP equipment and pipelines. FAC rate is determined by such factors as corrosion of metal, flow hydrodynamics, geometry of equipment elements and pipelines, applied water chemistry regimes (WCR), duration of operation, chemical composition of the metal, thickness of deposited corrosion product film and others. Approaches to the assessment of FAC rate according to the control data are addressed in the present study. Implemented investigation was aimed at the substantiation of the methodology of calculation of FAC rate. Absence of the methodology for calculation of FAC rate does not allow verification of calculation programs, as well as the use of data of regulatory documents on the minimum permissible thicknesses [1] for evaluating the residual lifetime. Processing of measured data allowed determining the main indexes of FAC process such as the values of wall thinning and thickening, rates of wall thinning and thickening, residual operation time to the moment of reaching the minimum permissible thickness. Reduction of thickness is determined by corrosion of metal and its increase is determined by the formation of deposited film of corrosion products. The process of corrosion products deposition on the internal surfaces of the element proceeds simultaneously with the process of thinning of the wall. Presence of this process results in the situation when the residual lifetime of equipment elements under the conditions of deposition of corrosion products is technically increased. At the same time the real state of the wall under the layer of deposited corrosion products is unknown, as well as the initial wall thickness. In order to bring the calculated results closer to the real situation it is necessary to use substantiated and verified methodology in the calculations of FAC rate according to the data of control measurements. The implemented study allowed suggesting the methodology of calculation of FAC rate taking into account the technological tolerances on the sizes and taking into account the influence of deposits on the initial and minimum thicknesses. Safety factor was also introduced for calculating the residual lifetime which is taken into account in the international practices because of the same reason. Introduction of correction coefficients allows enhancing the conservatism of calculations of residual lifetime characteristics by approximately 2.5 times compared with calculations performed on the base of nominal thickness. Document type: Article

Abstract

SUMMARY This article investigates charging strategies for plug-in hybrid electric vehicles (PHEV) as part of the energy system. The objective was to increase the combined all-electric mileage (total distance driven using only the traction batteries in each PHEV) when the total charging power at each workplace is subject to severe limitations imposed by the energy system. In order to allocate this power optimally, different input variables, such as state-of-charge, battery size, travel distance, and parking time, were considered. The required vehicle mobility was generated using a novel agent-based model that describes the spatiotemporal movement of individual PHEVs. The results show that, in the case of Helsinki (Finland), smart control strategies could lead to an increase of over 5% in the all-electric mileage compared to a no-control strategy. With a high prediction error, or with a particularly small or large battery, the benefits of smart charging fade off. Smart PHEV charging strategies, when applied to the optimal allocation of limited charging power between the cars of a vehicle fleet, seem counterintuitively to provide only a modest increase in the all-electric mileage. A simple charging strategy based on allocating power to PHEVs equally could thus perform sufficiently well. This finding may be important for the future planning of smart grids as limiting the charging power of larger PHEV fleets will sometimes be necessary as a result of grid restrictions. Copyright © 2013 John Wiley & Sons, Ltd.

Abstract

This article is concerned with application of finite element model updating to a part of a secondary feed water pipeline of a VVER type nuclear power plant. A mathematical model of the pipeline was produced with finite element method. The pipeline was subjected to modal testing in three different conditions. The results of the modal testing were then compared with those predicted with the model. This comparison revealed discrepancies between these two sets of results. It is a commonly known fact that incorrect values of parameters in a model, among other things, do cause these discrepancies. In order to improve the correlation between the measured and the predicted results and hence improve the reliability of the model, the model was subjected to finite element model updating. In this updating process, incorrect values of parameters in a model are adjusted, so that a desired level of correlation between measured and predicted results is achieved. As a result, the correlation between the measured and the predicted results was improved. The bulk of the improvement was achieved by adjusting the values of those parameters that were associated with boundary conditions of the model.

Abstract

A key issue in smart grid visions is the integration of the energy and mobility systems. Electric vehicles (EVs) can be charged with renewable photovoltaic (PV) solar power, and contribute to the integration of solar power in the electricity network via vehicle-to-grid systems. In such systems the role of consumers becomes crucial as they both generate and store energy. We investigate differences between PV and EV adopter groups and the implications of these differences for the transition to smart energy systems. We study how socio-demographic characteristics of the consumer base influence regional diffusion patterns. In turn, we build scenarios to explore the influence of diffusion patterns on the viability of regional EV-PV integration in terms of energy use and regional self-consumption. The results point out large differences in the spatial diffusion patterns between EV and PV. These differences have implications for the transition to smart sustainable grids; vehicle-to-grid systems may not be viable for certain regions.

Abstract

The impetus of the internal combustion engine developments is the reductions of the fuel consumptions and exhaust emissions. Thermal management is an efficient method to decrease the exhaust emissions and enhance fuel economy. In order to further optimize the thermal management of internal combustion engines, a detailed analysis of the energy flow in each component of internal combustion engines is indispensable. In this paper, the test bench of a heavy duty diesel engine was established to obtain the target parameters. The energy distributions in each component of the diesel engine, including compressor, intercooler, shaft power, turbine, coolant and exhaust, were calculated using tested parameters. The lubricating oil consumption was also taken into consideration. In addition, the potential influences of different turbochargers on the total thermal efficiency were analyzed. The results showed that the thermal efficiency of the diesel engine was more than 38% when the engine operated at 50%–100% engine load and 1000 rpm–1700 rpm conditions. The energy loss by coolant was more than 50% of the total fuel energy consumption in the low power output conditions. However, it was lower than 30% in high power output conditions, and the thermal loss was more than 150 kW around rated power conditions. The maximum proportion of the energy being consumed by turbine was ∼10% of the fuel energy; additionally, the exhaust energy distributions changed significantly after the turbine expansion. 1%–3% of the fuel energy was recycled by the turbocharger, then, flowed into the cylinders. The energy loss through the intercooler accounted for ∼6% of the fuel energy. Significant reductions of exhaust emissions and fuel consumptions can be achieved by optimizing the coolant and lubricating oil thermal conditions. Turbochargers presented a huge effect on exhaust temperature distributions at high power output conditions, and the total thermal efficiency changed significantly if all kinds of energy recovery approaches were applied.

Abstract

We studied to what extent perceived adoption norms affect the likelihood of adopting sustainable innovations, next to evaluations of the instrumental, environmental and symbolic attributes of these innovations. As hypothesised, results showed that people are more likely to adopt a sustainable innovation the more they evaluate the attributes of these sustainable innovations favourably and the more they think significant others would consider adoption (i.e., when adoption norms are strong). Moreover, we hypothesised and found that positive evaluations of the symbolic attributes are more likely to promote the adoption of sustainable innovations when people expect that few significant others would consider adoption. These findings suggest that weak adoption norms that are typical in the early adoption stage may both inhibit and promote adoption of sustainable innovations, via different routes.

Abstract

The European Commission fourth framework programme project ‘Assessment of passive safety injection systems of advanced light water reactors’ involved experiments on the PACTEL test facility and computer simulations of selected experiments. The experiments focused on the performance of passive safety injection systems (PSIS) of advanced light water reactors (ALWRs) in small break loss-of-coolant accident (SBLOCA) conditions. The PSIS consisted of a core make-up tank (CMT) and two pipelines. A pressure balancing line (PBL) connected the CMT to one cold leg. The injection line (IL) connected it to the downcomer. The project involved 15 experiments in three series. The experiments provided information about condensation and heat transfer processes in the CMT, thermal stratification of water in the CMT, and natural circulation flow through the PSIS lines. The project included validation of three thermal-hydraulic computer codes (APROS, CATHARE and RELAP5). The analyses showed the codes are capable of simulating the overall behaviour of the transients. The codes predicted accurately the core heatup, which occurred when the primary coolant inventory was reduced so much that the core top became free of water. The detailed analyses of the calculation results showed that some models in the codes still need improvements. Especially, further development of models for thermal stratification, condensation and natural circulation flow with small driving forces would be necessary for accurate simulation of the phenomena in the PSIS.