In the present work, a numerical investigation has been performed to study the thermal behavior of a flow through a pulsed detonation thermal spray device that employs a hydrogen-air mixture. In this device, a detonation wave travels inside a detonation tube and eventually exits the tube and impinges against a substrate. Two types of substrates have been investigated, namely, a sphere and a flat-plate. The present model is based on solving the two dimensional, axisymetric Euler reactive flow equations with temperature-dependent specific heats. A global single step finite rate reaction has been considered. The present results demonstrate the effects of two main parameters on the thermal performance of the device under consideration. These parameters are: the size and shape of the substrate, and the stand off distance.