Effect of hole arrangement patterns on the leakage and rotordynamic characteristics of the honeycomb seal

Abstract

The honeycomb seal is a vital component to reduce the leakage flow and improve the system stability for the turbomachines. In this work, a three-dimensional model is established for the interlaced hole honeycomb seal (IHHCS) and the non-interlaced hole honeycomb seal (NIHHCS) to investigate its leakage and rotordynamic characteristics by adopting computational fluid dynamics (CFD). Results show that the hole arrangement patterns have little impact on the pressure drop and turbulence kinetic energy distribution for the seals, and the IHHCS possesses a slightly lower leakage flow rate than the NIHHCS. Moreover, the numerical results also show that the NIHHCS possesses a better rotordynamic performance than the IHHCS at all investigated conditions. Both seals show a larger k and a lower C_eff with the increase of the positive preswirl ratios and rotational speeds, while the negative preswirl ratios would reduce the k and improve the C_eff. The NIHHCS possesses a higher absolute value of F_t for all operating conditions, this could explain the distinction of C_eff for both seals at different working conditions.