In this paper, the existence of the exponential attractor for the thermohydraulics equations is proved, and the estimates of its fractal dimensions are also given.
In order to verify the simulation results of the liquid metal target and the granular flow target, the spallationtarget laboratory have established several experimental benches and carried out some related experiments...In order to verify the simulation results of the liquid metal target and the granular flow target, the spallationtarget laboratory have established several experimental benches and carried out some related experiments on thesebenches.1. Liquid Target ResearchA water loop has been established in 2012 for investigating the flow behaviors of water in windowless target andhas been rebuilt in 2014 for experiments of window target. The experiments are conducted in an approximately 1:1sized window target model shown in Fig. 1. The flow pattern inside the spallation area is visualized by means ofthe particle image velocimetry (PIV). The flow range of the present experiment is between 8.4 and 20 m3/h, andseveral typical flow patterns are observed under the conditions of different inlets and outlets.展开更多
The mathematical model of turbulent buoyant recirculating flows is applied in thermohydraulics and an algebraic stress model is proposed to simulate noniso- tropic turbulent buoyant recirculating flows in a shallow wa...The mathematical model of turbulent buoyant recirculating flows is applied in thermohydraulics and an algebraic stress model is proposed to simulate noniso- tropic turbulent buoyant recirculating flows in a shallow water channel.It can be shown that the buoyancy force is able to reduce the turbulence in vertical di- rection and the heat conduction in the thermocline layer is nonisotropic.At the same time,the stacked-up and separated arrangement of intake-outlet for thermal power stations have been predicted by such numerical models.The results are in good agreement with experiments(ref.1-3).展开更多
In this article,the thermal–hydraulic efficacy of a boehmite nanofluid with various particle shapes is evaluated inside a microchannel heat sink.The study is done for particle shapes of platelet,cylinder,blade,brick,...In this article,the thermal–hydraulic efficacy of a boehmite nanofluid with various particle shapes is evaluated inside a microchannel heat sink.The study is done for particle shapes of platelet,cylinder,blade,brick,and oblate spheroid at Reynolds numbers(Re)of 300,800,1300,and 1800.The particle volume fraction is assumed invariant for all of the nanoparticle shapes.The heat transfer coefficient(h),flow irregularities,pressure loss,and pumping power heighten by the elevation of the Re for all of the nanoparticle shapes.Also,the nanofluid having the platelet-shaped nanoparticles leads to the greatest h,and the nanofluid having the oblate spheroid particles has the lowest h and smallest pressure loss.In contrast,the nanofluid having the platelet-shaped nanoparticles leads to the highest pressure loss.The mean temperature of the bottom surface,thermal resistance,and temperature distribution uniformity decrease by the rise in the Reynolds number for all of the particle shapes.Also,the best distribution of the temperature and the lowest thermal resistance are observed for the suspension containing the platelet particles.Thereby,the thermal resistance of the nanofluid with the platelet particles shows a 9.5%decrement compared to that with the oblate spheroid particles at Re=300.For all the nanoparticle shapes,the figure of merit(FoM)uplifts by elevating the Re,while the nanofluids containing the brickand oblate spheroid-shaped nanoparticles demonstrate the highest FoM values.展开更多
文摘In this paper, the existence of the exponential attractor for the thermohydraulics equations is proved, and the estimates of its fractal dimensions are also given.
文摘In order to verify the simulation results of the liquid metal target and the granular flow target, the spallationtarget laboratory have established several experimental benches and carried out some related experiments on thesebenches.1. Liquid Target ResearchA water loop has been established in 2012 for investigating the flow behaviors of water in windowless target andhas been rebuilt in 2014 for experiments of window target. The experiments are conducted in an approximately 1:1sized window target model shown in Fig. 1. The flow pattern inside the spallation area is visualized by means ofthe particle image velocimetry (PIV). The flow range of the present experiment is between 8.4 and 20 m3/h, andseveral typical flow patterns are observed under the conditions of different inlets and outlets.
文摘The mathematical model of turbulent buoyant recirculating flows is applied in thermohydraulics and an algebraic stress model is proposed to simulate noniso- tropic turbulent buoyant recirculating flows in a shallow water channel.It can be shown that the buoyancy force is able to reduce the turbulence in vertical di- rection and the heat conduction in the thermocline layer is nonisotropic.At the same time,the stacked-up and separated arrangement of intake-outlet for thermal power stations have been predicted by such numerical models.The results are in good agreement with experiments(ref.1-3).
文摘In this article,the thermal–hydraulic efficacy of a boehmite nanofluid with various particle shapes is evaluated inside a microchannel heat sink.The study is done for particle shapes of platelet,cylinder,blade,brick,and oblate spheroid at Reynolds numbers(Re)of 300,800,1300,and 1800.The particle volume fraction is assumed invariant for all of the nanoparticle shapes.The heat transfer coefficient(h),flow irregularities,pressure loss,and pumping power heighten by the elevation of the Re for all of the nanoparticle shapes.Also,the nanofluid having the platelet-shaped nanoparticles leads to the greatest h,and the nanofluid having the oblate spheroid particles has the lowest h and smallest pressure loss.In contrast,the nanofluid having the platelet-shaped nanoparticles leads to the highest pressure loss.The mean temperature of the bottom surface,thermal resistance,and temperature distribution uniformity decrease by the rise in the Reynolds number for all of the particle shapes.Also,the best distribution of the temperature and the lowest thermal resistance are observed for the suspension containing the platelet particles.Thereby,the thermal resistance of the nanofluid with the platelet particles shows a 9.5%decrement compared to that with the oblate spheroid particles at Re=300.For all the nanoparticle shapes,the figure of merit(FoM)uplifts by elevating the Re,while the nanofluids containing the brickand oblate spheroid-shaped nanoparticles demonstrate the highest FoM values.
