气膜孔布置形式对发动机中心锥冷却与红外抑制特性的影响

对发动机中心锥的红外抑制技术开展数值研究,在中心锥上采取气膜冷却技术,比较了不同气膜孔布置形式对冷却与红外抑制特征的影响。外涵低温气流通过支板引入中心锥,在锥体前端形成气膜覆盖,使支板与中心锥壁面得到了有效冷却。研究发现,采用气膜冷却后,喷管腔体壁面温度显著降低,中心锥与支板的壁面温度降低13.5%和14.6%。3～5 m波段上红外辐射得到有效抑制,喷管正后方最大降低41%,0～30范围内红外辐射特征得到显著抑制。     

高效太阳电池硅衬底特性对原子层沉积Al2O3薄膜钝化性能的影响

Atom layer deposition （ALD）-Al2O3 thin films are considered effective passivation layers for p-type silicon surfaces. A lower surface recombination rate was obtained through optimizing the deposition parameters. The effects of some of the basic substrate characteristics including material type, bulk resistivity and surface morphology on the passivation performance of ALD-Al2O3 are evaluated in this paper. Surface recombination velocities of 7.8 cm/s and 6.5 cm/s were obtained for p-type and n-type wafers without emitters, respectively. Substrates with bulk resistivity ranging from 1.5 to 4 Ω · cm were all great for such passivation films, and a higher implied Voc of 660 mV on the 3 Ω · cm substrate was achieved. A minority carrier lifetime （MCL） of nearly 10 μs higher was obtained for cells with a polished back surface compared to those with a textured surface, which indicates the necessity of the polishing process for high-efficiency solar cells. For n-type semi-finished solar cells, a lower effective front surface recombination velocity of 31.8 cm/s was acquired, implying the great potential of （ALD）-Al2O3 thin films for high-efficiency n-type solar cells.