Particle manipulation using laser beam is almost a new and contactless technique in particulate sciences. The method is based on the radiation pressure of light photons on the particles suspended in a semi-transparent fluid. Applications of the technique mainly cover microscopic separation and detection of biological objects. In this work, a theoretical study is conducted to investigate the hydrodynamic and thermal effects on a particulate flow in a mini-channel. Laser thermal effects are studied as a result of light absorption either in fluid or dispersed phase. An analytical model is developed to be the real simulator of a test bed developed by the authors. The main objective of performed simulation is to determine the conditions of hydrodynamic laser-particle interaction and the contribution of thermal effects. More specifically, the criteria for size of particles and beam parameters to meet the mentioned conditions are presented. The model results are used for design and selection of elements in a particle manipulation system.