Development and Performance Testing of Flexible ...

Development and Performance Testing of Flexible Heat Pipe for Spacecraft Applications Lakshya Gangwar Mentor:- Prof. Sameer Khandekar Department of Mechanical Engineering, Indian Institute of Technology Kanpur, India

INTRODUCTION

RESULTS AND DISCUSSIONS

 This research describes the development, testing, and characterization of bellow used in fabrication of a flexible heat pipe.

Axial Stiffness Axial stiffness is calculated experimentally and compared with theoretical models as well as with simulations. Theoretical Axial stiffness :1. As per Harignx formulation:- K=203.9 N/mm 2. As per Reissner formulation:- K=494.2 N/mm 3. As per EJMA standard:K=407.53 N/mm

 The heat pipe is being designed for thermal management of satellites and for other space applications wherein passive heat transfer is required to be coupled with vibration isolation requirements.  Analysing Axial, angular and lateral characteristics of bellow using experimentation, FEM simulation and theoretical modelling

EXPERIMENTS AND SIMULATIONS

Experimental:- K=403 N/mm

Simulation:- K=454.5 N/mm

Lateral Stiffness Lateral stiffness is calculated theoretically and compared with simulation.

Experimental setup showing bellow mounted on table. One end is clamped with C-clamp while at other end load is applied using weights. Laser sensor mounted X ray CT scan of bellow performed above bellow is used to measure to find actual thickness of bellow which comes out to be 0.263 mm deflection of bellow.

1. Using EI as per Harignx formulation:K=6.304 N/mm 2. Using EI as per Reissner formulation:K=15.83 N/mm 3. As per EJMA: K=14.64 N/mm • FEM Simulation :K=16.95 N/mm

Angular Stiffness Case-1: (Pure Bending)Angular stiffness is calculated theoretically and compared with simulation. FEM Simulation showing Lateral deformation of Bellow

Stress analysis and Design thickness of bellow

1. Using EI as per Harignx formulation:K=1.404 N.m 2. Using EI as per Reissner formulation:K=3.526 N.m 3. As per EJMA: K=3.26 N.m • FEM Simulation:K=3.55 N.m Case 2:- (Tip Loading) Angular stiffness is calculated theoretically and compared with experiment and simulation.

Since, Stress as well as Kaxial varies sensitively with thickness of bellow Design Criterion (at 60 bar):- S3+S4 =0.168mm (yield stress); h>=0.258mm (allowable stress) Kaxial