The aim of this paper is to develop a simple EV model and predict its energy consumption with a variable and fixed ratio gearbox over a standard driving cycle in order to understand whether this could offer significan...The aim of this paper is to develop a simple EV model and predict its energy consumption with a variable and fixed ratio gearbox over a standard driving cycle in order to understand whether this could offer significant efficiency gains. The powertrain of a generic electric vehicle was modelled in Matlab / Simulink using the QSS Toolkit. The electric vehicle was then fitted with different transmissions with different levels of complexity. Simulations were done to investigate the energy consumptions across 6 standard driving cycles. The emerging conclusions are that it is possible to improve overall energy consumption levels by around 5 to 12 % with a variable ratio gearbox depending on the driving cycle used. However, there are many other practical considerations which must be weighed against this positive result - and the paper discusses the impact of several of these such as, gearbox efficiency, additional weight, cost and complexity, effect on drivability and potential for motor downsizing.展开更多
A prototype cleanroom for hazardous testing and handling of satellites prior to launcher encapsulation,satisfying the ISO8 standard has been designed and analyzed in terms of performances.Unsteady Reynolds Averaged Na...A prototype cleanroom for hazardous testing and handling of satellites prior to launcher encapsulation,satisfying the ISO8 standard has been designed and analyzed in terms of performances.Unsteady Reynolds Averaged Navier-Stokes(URANS)models have been used to study the related flow field and particulate matter(PM)dispersion.The outcomes of the URANS models have been validated through comparison with equivalent large-eddy simulations.Special attention has been paid to the location and shape of the air intakes and their orientation in space,in order to balance the PM convection and diffusion inside the cleanroom.Forming a cyclone-type flow pattern inside the cleanroom is a key to maintaining a high ventilation efficiency.展开更多
The aim of this study was to investigate whether fish size has an effect on the utilisation efficiency of digestible protein,digestible fat and digestible carbohydrates(Carb)for energy gain in rainbow trout.Four diffe...The aim of this study was to investigate whether fish size has an effect on the utilisation efficiency of digestible protein,digestible fat and digestible carbohydrates(Carb)for energy gain in rainbow trout.Four different diets ranging in protein,fat and Carb were fed to two size classes of rainbow trout,30 to 75 g and 92 to 214 g,at three different feeding levels(12,8 and 4 g/kg0.8 per day).This led to 24 treatments with 2 replicates(tanks).Tanks contained 36 fish for the 30 to 75 g fish and 24 fish for the 92 to 214 g fish.Faeces was collected for the determination of the digestibility of protein,fat and Carb.Energy retention was determined from the initial and final body composition.The design of this trial allowed for multiple regression analysis to determine the utilisation efficiency of the different digestible macronutrients for energy gain.By doing so,it was also possible to establish specific net energy(NE)formulae for 30 to 75 g and 92 to 214 g rainbow trout.The results showed that there were differences between the two size classes in the estimated NE formulae and the corresponding partial efficiencies of digestible protein,fat and Carb for NE(k_(gNE,CP),k_(gNE,Fat) and k_(gNE,Carb)).The k_(gNE,CP) was not different(P=0.586)between the two size classes(on average 76%),but the k_(gNE,Fat) decreased(P=0.005)from 82%to 65%in the bigger fish and the k_(gNE,Carb) showed a tendency(P=0.077)to increase from 55%to 73%in the bigger fish.The findings of this study showed that fish size has an effect on the estimation of net energy in feeds for rainbow trout.展开更多
Kuiper and Jessup（1993）developed a design method for propellers in a wake based on the Eppler foil design method.The optimized section is transformed into the three-dimensional propeller flow using the approach of t...Kuiper and Jessup（1993）developed a design method for propellers in a wake based on the Eppler foil design method.The optimized section is transformed into the three-dimensional propeller flow using the approach of the effective blade sections.Effective blade sections are two-dimensional sections in two-dimensional flow which have the same chordwise loading distribution as the three-dimensional blade sections of a propeller.However,the design procedure is laborious in two aspects：finding an optimum blade section using the Eppler program requires much skill of the designer,and transforming the two-dimensional blade section into a propeller blade section in three-dimensional flow is complex.In this work,these two problems were coped with.A blade section design procedure was presented using an optimization technique and an alternative procedure for the effective blade section is developed using a lifting surface design method.To validate the method a benchmark model of a naval ship was used.This benchmark model was extended by new appendices and a reference propeller,and designed using conventional design methods.This reference propeller was optimized using the new design procedure and model tests were carried out.Special attention was given to the data of the model and the reference propeller,to make the configuration suitable for the Reynolds-Averaged Navier-Stokes（RANS）calculations.展开更多
文摘The aim of this paper is to develop a simple EV model and predict its energy consumption with a variable and fixed ratio gearbox over a standard driving cycle in order to understand whether this could offer significant efficiency gains. The powertrain of a generic electric vehicle was modelled in Matlab / Simulink using the QSS Toolkit. The electric vehicle was then fitted with different transmissions with different levels of complexity. Simulations were done to investigate the energy consumptions across 6 standard driving cycles. The emerging conclusions are that it is possible to improve overall energy consumption levels by around 5 to 12 % with a variable ratio gearbox depending on the driving cycle used. However, there are many other practical considerations which must be weighed against this positive result - and the paper discusses the impact of several of these such as, gearbox efficiency, additional weight, cost and complexity, effect on drivability and potential for motor downsizing.
基金funded by Space Research and Innovation Network (www.sprint.ac.uk)for Technology Grants (OW131743P4V4M,OW131797P4V2B,ZX and CY)grateful to NERC (www.nerc.ac.uk)for the Grant (NE/W002841/1,ZX)to complete the writing of the paper。
文摘A prototype cleanroom for hazardous testing and handling of satellites prior to launcher encapsulation,satisfying the ISO8 standard has been designed and analyzed in terms of performances.Unsteady Reynolds Averaged Navier-Stokes(URANS)models have been used to study the related flow field and particulate matter(PM)dispersion.The outcomes of the URANS models have been validated through comparison with equivalent large-eddy simulations.Special attention has been paid to the location and shape of the air intakes and their orientation in space,in order to balance the PM convection and diffusion inside the cleanroom.Forming a cyclone-type flow pattern inside the cleanroom is a key to maintaining a high ventilation efficiency.
文摘The aim of this study was to investigate whether fish size has an effect on the utilisation efficiency of digestible protein,digestible fat and digestible carbohydrates(Carb)for energy gain in rainbow trout.Four different diets ranging in protein,fat and Carb were fed to two size classes of rainbow trout,30 to 75 g and 92 to 214 g,at three different feeding levels(12,8 and 4 g/kg0.8 per day).This led to 24 treatments with 2 replicates(tanks).Tanks contained 36 fish for the 30 to 75 g fish and 24 fish for the 92 to 214 g fish.Faeces was collected for the determination of the digestibility of protein,fat and Carb.Energy retention was determined from the initial and final body composition.The design of this trial allowed for multiple regression analysis to determine the utilisation efficiency of the different digestible macronutrients for energy gain.By doing so,it was also possible to establish specific net energy(NE)formulae for 30 to 75 g and 92 to 214 g rainbow trout.The results showed that there were differences between the two size classes in the estimated NE formulae and the corresponding partial efficiencies of digestible protein,fat and Carb for NE(k_(gNE,CP),k_(gNE,Fat) and k_(gNE,Carb)).The k_(gNE,CP) was not different(P=0.586)between the two size classes(on average 76%),but the k_(gNE,Fat) decreased(P=0.005)from 82%to 65%in the bigger fish and the k_(gNE,Carb) showed a tendency(P=0.077)to increase from 55%to 73%in the bigger fish.The findings of this study showed that fish size has an effect on the estimation of net energy in feeds for rainbow trout.
文摘Kuiper and Jessup（1993）developed a design method for propellers in a wake based on the Eppler foil design method.The optimized section is transformed into the three-dimensional propeller flow using the approach of the effective blade sections.Effective blade sections are two-dimensional sections in two-dimensional flow which have the same chordwise loading distribution as the three-dimensional blade sections of a propeller.However,the design procedure is laborious in two aspects：finding an optimum blade section using the Eppler program requires much skill of the designer,and transforming the two-dimensional blade section into a propeller blade section in three-dimensional flow is complex.In this work,these two problems were coped with.A blade section design procedure was presented using an optimization technique and an alternative procedure for the effective blade section is developed using a lifting surface design method.To validate the method a benchmark model of a naval ship was used.This benchmark model was extended by new appendices and a reference propeller,and designed using conventional design methods.This reference propeller was optimized using the new design procedure and model tests were carried out.Special attention was given to the data of the model and the reference propeller,to make the configuration suitable for the Reynolds-Averaged Navier-Stokes（RANS）calculations.
