Heat transfer in liquid helium

摘要: Publisher Summary This chapter focuses on the practical problems faced in design of cryogenic devices. It illustrates two problems. First, heat transfer are often regimes far from those that fundamental research can even contemplate tackling at present time. Second, terminology used is baffling to physicist, and there a substantial barrier communication between pure applied communities. To cope with these problems, makes rough division discussion into low transfer, where methods language one accustomed likely apply, high real technological be found. help overcome assist developing common terminology. The discusses Kapitza resistance. noted when flows across boundary liquid helium solid, temperature difference appears boundary. phenomenon referred as “acoustic mismatch theory.” theory derives its name assumption thermal energy solid carried by acoustic phonons media differ elastic properties, thus “mismatched,” their respective impedances.