Experimental and Numerical Investigation on Thermal Management of an Outdoor Battery Cabinet

Many forms of electronic equipment such as battery packs and telecom equipment must be stored in harsh outdoor environment. It is essential that these facilities be protected from a wide range of ambient temperatures and solar radiation. Temperature extremes greatly reduce lead-acid based battery performance and shorten battery life. Therefore, it is important to maintain the cabinet temperature within the optimal values between 20oC and 30oC to ensure battery stability and to extend battery lifespan. To this end, cabinet enclosures with proper thermal management have been developed to house such electronic equipment in a highly weather tight manner, especially for battery cabinet. In this paper, the flow field and temperature distribution inside an outdoor cabinet are studied experimentally and numerically. The battery cabinets house 24 batteries in two configurations namely, two-layer configuration and six-layer configuration respectively. The cabinet walls are maintained at a constant temperature by a refrigeration system. The cabinet’s ability to protect the batteries from an ambient temperature as high as 50oC is studied. An experimental facility is developed to measure the battery surface temperatures and to validate the numerical simulations. The differences between the experimental and computational fluid dynamic (CFD) results are within 5%

Investigation on Moisture and Salt Transport in Heterogeneous Porous Media of Relics-Soil in Archaeology Museum

The unearthed relics in archaeology museum are usually being presented to the public as still partly connected to their primitive environment. Migration of moisture may cause the carbonate from the soil being deposited on the relic’s surface and some carbonates would react with the penetrating SO2 to form sulphates, which will change the relics’ primitive form and material properties. In this research, experiments were carried out to clarify the migration mechanism of water and salt in a soil-relic-atmosphere coupling environment. The research results show that there existing a one-way transport of moisture from the soil-relics to the air even though the relative humidity approximates to 100%. Meanwhile, the effects of soil properties, air temperature, relative humidity and salt concentration on the transports of moisture and salt are identified

Numerical and Experimental Investigation on Thermal Management of an Outdoor Battery Cabinet

Many forms of electronic equipment, of necessity, must be located in an outdoor environment. Such equipment in typical form may be battery packs or telecom-equipment. It is essential that these facilities be protected from a wide range of ambient temperatures and solar radiation. To this end, cabinet enclosures with proper thermal management have been developed to house such electronic equipment in a highly weather tight manner, especially for battery cabinet. Often the batteries are of a lead-acid construction which is known to be adversely affected by temperature extremes in terms of battery performance and life. Therefore, it is important to maintain the cabinet temperature ideally for ensuring battery stability and extending battery lifespan. In this paper, physical and mathematical models are established to investigate the flow field and temperature distribution inside an outdoor cabinet, which contains 24 batteries with two configurations of two-layer and six-layer respectively. The cabinet walls are maintained at a constant temperature by a refrigeration system and the ambient temperature is up to 50 °C according to the practical situation. The flow field and temperature distribution are analyzed with and without consideration of solar radiation. An experimental facility is then developed to measure the battery surface temperatures and to validate the numerical simulation. The differences between the CFD and experimental results are within 2%, which confirms the CFD model

Decays of the J/ ψ to [formula omitted] and [formula omitted] final states

With 7.8 million produced J/ ψ events collected by the BES detector at the BEPC, decays J/ψ→Λ Λ,Λ Λγ and Λ Λπ 0 are analysed. The branching ratios are measured to be Br(J/ψ→Λ Λ)=(1.08±0.06±0.24)×10 −3 , Br(J/ψ→Λ Λγ)<1.6×10 −4(90% C.L.) , Br(J/ψ→Λ Λπ 0)=(2.3±0.7±0.8)×10 −4 , respectively. The angular distribution for J/ψ→Λ Λ is of the form dN d cosθ =N 0(1+α cos 2θ) , from which we determine α=0.52±0.33±0.13

The BES upgrade

The Beijing Spectrometer (BES) detector is a general purpose solenoid detector at the Beijing Electron Positron Collider (BEPC) in Beijing, China, that has collected large numbers of J/ψ, ψ′, D s, D and τ events. In this paper, we describe the recent upgrade of the initial BES detector (BESI) to the improved BESII detector