Tip clearance variation and its influence on a 3-stage low pressure fan performance in different operating conditions were studied using model and numerical simulation method. According to prediction results of tip clearance prediction model

the tip clearance variation of the 3-stage low pressure fan was mainly associated with the rotating speed

and the tip clearance variation from choke condition to near stall condition was small at the same rotating speed. Based on these characteristics

an evaluation method about the influence on the stability margin with tip clearance variation was found. The performance of a 3-stage low pressure fan was simulated in different operating conditions to allow a comparison by using the predicted tip clearance or not. The results show that the influence with tip clearance variation increases along with the growing rotating speed

and the tip clearance variations has a 0.5% impact on the calculated mass flow rate at inlet

0.5% impact on the calculated maximum efficiency and 5% impact on the calculated stability margin at the 100% design rotating speed.