背负式弥雾喷粉机射流规律和射程的研究

<正> 在农林业生产中,背负式弥雾喷粉机是应用广泛、拥有量较大的一种病虫害防治机械。现有的机具喷射高度往往不能适应高大林木的要求,使用上受到限制。研制具有高射程性能的机具以满足林业生产的需要,是研制森林病虫害防治机械的重要课题之一。 过去国内外主要侧重于这种机具的药物喷洒质量和风机性能方面的研究,近年虽已注意射流规律对射程的影响问题,但缺乏系统的理论和试验研究。 本研究在模拟等温自由淹没紊动射流的环境条件下,通过试验测定了弥雾喷粉机喷射单相空气流时的射流特性及射程。并在风机试验台上实测了相应工作状态下的射流紊流系数,喷嘴出口气流参数及喷洒部件和风机的气动性能。在试验的基础上分析讨论了弥雾喷粉机实际射流规律。依据流体力学和风机基础理论,从实际射流规律、喷嘴型式、喷洒部件和风机工况性能等方面论证了影响机具射程的因素。

A STUDY OF EFFLUX PROPERTIES AND RANGE OF KNAPSACK MISTER-DUSTERS

This paper deals with efflux properties of knapsack mister-dusters as well as factors affecting the range of the equipment.Efflux properties of single-phase airflow from the equipment and aerodynamic characteristics of the equipment are analyzed on the basis of the tests. The results show that theory of ideal isothermal free turbulent jet () is applicable to velocity distribution at the fully developed turbulent region in actual airflow of the equipment and to fading effect of velocity at its axis; turbulent coefficient is a key factor affecting the effective range. A constrictor nozzle can uniform the velocity of airflow passing through it, thus being highly recommended to improve the range of equipment. Structure and aerodynamic characteristics of spraying parts and performance of a blower also affect the range greatly. In addition, available power of the blower should be matched with rated power of its engine to reach the full range.This paper provides information for further improvement of the range of knapsack mister-dusters and for development of new products with higher range to meet the needs of forestry as well.