Design study of impact performance of a DTH hammer using PQRSM and numerical simulation

Abstract

This paper presents a simulation model to predict the percussive drilling performance of a down-the-hole (DTH) hammer. First, the pneumatic dynamic model of the DTH hammer is developed considering mass flow rate relations representing orifice opening areas of the air tube, the piston, and the bit flushing channels. Next, the performance of the DTH hammer is numerically simulated and evaluated by considering fluctuations of the upper and lower chamber pressure, impact frequency, and force. The simulation model is validated through a series of laboratory tests. Finally, design factors influencing the hammers impact performance are selected via screening design, and the progressive quadratic response surface method then optimizes the set of design factors to propose a design modification to increasing the impact performance of the DTH hammer.