ISRO has launch vehicles PSLV, GSLV, GSLV Mk3, SSLV. Solid motors are sued as boosters. Performance of solid motor depends upon the grain properties, grain geometry, nozzle parameters and burning surface area.

Presence of gas bubbles increases the surface area and affect the performance (chamber pressure) of solid motor. Blow holes (casting defect) are formed in the propellant grain due to presence of gas / vapour in the solid propellant grain due to various sources. During propellant casting, size, shape and orientation of gas bubble changes.

Based on the literature review, data is available related to bubble rise phenomenon Newtonian fluids, non-Newtonian fluids. But there is a research gap available in the field of bubble rise phenomenon in viscoelastic propellant slurry.

Experimental setup was configured and realized for bubble rise experiment. With necessary clearances, several experiments were conducted by injecting bubble of sizes O10mm, O 14mm, O 25mm, O 33mm in propellant slurry.

Bubble rise velocity was measured and correlations were developed for bubble rise velocity as a function of bubble diameter and propellant slurry viscosity.