REG NASA-LLIS-0496-1997 Lessons Learned - Improper Welded Joints in Rocket Engine Combustion Chamber (1995).pdf

1、Lessons Learned Entry: 0496Lesson Info:a71 Lesson Number: 0496a71 Lesson Date: 1997-03-13a71 Submitting Organization: JPLa71 Submitted by: C. GuernseySubject: Improper Welded Joints in Rocket Engine Combustion Chamber (1995) Abstract: A defective weld in the combustion chamber of the Mars Global Sur

2、veyor main engine resulted in destruction of the engine within the first few seconds of test. Conduct a thorough external and internal inspection of rocket engine combustion chambers, paying particular attention to welded joints, prior to hot fire testing.Description of Driving Event: In the first t

3、est firing of a Mars Global Surveyor (MGS) main engine, the engine was destroyed within a few seconds. The combustion chamber had exceeded the maximum allowable temperature, causing parts to melt and rendering the engine unusable. Internal examination with a boroscope revealed an annular extrusion i

4、n the combustion chamber due to overpenetration of weld material in the joint between the injector and the chamber.The MGS main engine injector fits over the head end of the combustion chamber; the two parts are attached with a weld about the circumference of an overlapping joint. Vendor use of an i

5、ncorrect weld schedule produced an annular ridge, which interfered with the flow of boundary layer cooling fuel within the chamber. This disturbed flow resulted in an untenable thermal condition.A boroscopic examination of the chamber prior to the test firing would have revealed the defect.Lesson(s)

6、 Learned: Conduct a thorough external and internal inspection of rocket engine combustion chambers, paying particular attention to welded joints, prior to hot fire testing.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Recommendation(s): N/AEvidence

7、 of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Hardwarea71 Test ArticleAdditional Info: Approval Info: a71 Approval Date: 1997-03-25a71 Approval Name: Carol Dumaina71 Approval Organization: 125-204a71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-