Intensity of the impact made by a gas-jet emitter on the surface layer of the loamy soil: research results

Abstract

It is an urgent task to develop the technology of surface soil loosening by compressed air based on an ultrasonic impact, because it provides volumetric loosening of the surface soil layer without a mechanical impact. The research was carried out to determine the degree of intensity of the compressed air jet impact in the ultrasonic oscillation mode on the surface layer of the loamy soil. For experimental studies, the authors made a gas-jet emitter with the axis of the outlet hole perpendicular to the axis of the impinging and reflected flow. The gas-jet emitter has the following geometrical characteristics: nozzle inlet diameter – 5.7 mm; nozzle critical orifice diameter – 2.9 mm; distance between the cross-section of the nozzle inlet and critical orifice – 5.9 mm; nozzle outlet diameter – 3.42 mm; distance between the cross-section of the critical and outlet orifices – 2.4 mm; distance between the nozzle and the resonator – 3.75 mm; diameter and depth of the resonator well – 3 mm; inner diameter of the working chamber – 12 mm; diameter of the outlet orifice – 5 mm. The reaction of the medium to the receiver pressure release in the range of 0.2 to 0.5 MPa was estimated by the depth of air jet penetration, a possibility of surface pitting, sample destruction, and the emergence of wide cracks. The authors studied soil samples with a diameter of 0.1 and a height of 0.05 m. As a result of the study, they established that at an absolute moisture value of the loamy soil of 17% and a hardness of 4.16 MPa, the depth of penetration of an air stream jet was 3 to 5 cm. The complete destruction of the soil sample corresponded to a receiver discharge pressure of 0.45 and 0.5 MPa. Surface pitting of the samples is characteristic for a receiver pressure drop in the range of 0.2 to 0.4 MPa. The articles concludes that for a gas-jet emitter with the claimed geometrical characteristics the distance between the nozzle and the resonator should be 3.75 mm, and the receiver discharge pressure should equal 0.4 MPa.