3 . a number of test parameters of insulation , position of reflux pipe inlet arrangemts , injection etc . are explored in the experiment . the experimental results demonstrate that the natural circulation is an efficient way to precool the pump system and maintain it at cryogenic temperatures 進(jìn)行了多組對(duì)比實(shí)驗(yàn),著重對(duì)兩種不同回流方式對(duì)于自然循環(huán)和預(yù)冷的影響進(jìn)行了比較,并研究了系統(tǒng)增壓、引射、回流管絕熱效果以及泵體絕熱效果對(duì)于自然循環(huán)的建立和維持以及對(duì)循環(huán)預(yù)冷效果的影響。