Copper/Graphite Composite at High Heat Flux Boiling Surface

研究计划的目的是通过实验和半理论研究铜-石墨复合材料表面的成核沸腾。这种复合材料（由SPARTA公司开发）由超高导热石墨纤维固结在铜基体中组成。该复合材料在纤维方向上的导热系数高，是其他方向的几倍。由于纤维的大小，它可以显著提高成核位点的活性。拟进行的研究将确定热流密度、站点人口密度、气泡生长速率、气泡离开频率和气泡离开大小。这个项目是密歇根大学和斯巴达公司的合作成果。斯巴达的铜/石墨复合材料已被用作美国宇航局航天飞机鼻锥的高温材料。由于其大量的极薄石墨纤维，复合材料有望在每单位面积上以核沸腾的形式除去大量的热量。如果这个概念得到实验验证，那么这种复合材料在工业上的应用将非常广泛，例如，在电子设备的冷却方面。本研究为验证其沸腾性能的概念验证型研究。

The objective of the research program is to investigate experimentally and semi-theoretically nucleate boiling from a copper-graphite composite surface. The composite (under development by SPARTA, Inc.) consists of ultra-high thermal conductivity graphite fibers consolidated in a copper matrix. The composite has a high thermal conductivity in the fiber direction which is several times those in the other directions. Due to the size of the fiber, it could significantly enhance the nucleation site activity. The proposed research will determine the heat flux, site population density, bubble growth rate, bubble departure frequency and bubble departure size. This project is a cooperative effort of the University of Michigan and SPARTA, Inc. The Sparta's Copper/Graphite composite has been used as the higher temperature material in the nose cone of the NASA space shuttles. Due to its large number of very thin graphite fibers, the composite is expected to remove a large amount of heat per unit area in the form of nucleate boiling. If the concept is experimentally verified, then the use of the composite in industry will be very broad, for example, in the cooling of electronic units. This research is a proof-of-concept type study for the verification of its boiling performance.