Abstract: In order to avoid the over-limit of dust concentration in crushing chamber and to obtain the rational parameters for the design of dust removal by ventilation， according to the similarity theory and the gas-solid two-phase flow motion equation， taking 27^# crushing chamber in Xishimen Iron Mine as the background， the similarity index was deduced and a similarity model device was designed for the specific situation in the crushing chamber. Meanwhile， the dust concentration distribution was studied. The results indicated that dust concentration reached the maximum value near the mouth region in the crusher， while it gradually reduced along the radial direction in this region. The higher wind velocity and ore moisture are， the lower the dust concentration is. In addition， when ore moisture reached the value of 3.02%， the dust concentration no longer reduced. After the installation of exhaust dedusting system， the dust concentration was below 2mg/m³， and the average removal rate reached 90%.

Key words: crushing chamber, dust, similarity criterion, gas-solid two-phase flow, concentration distribution