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 進行了多組對比實驗,著重對兩種不同回流方式對于自然循環(huán)和預(yù)冷的影響進行了比較,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于自然循環(huán)的建立和維持以及對循環(huán)預(yù)冷效果的影響。