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当由靠近工作区的送风口送出的风量很大时,需要使射流的速度和射流与环境空气的温差能尽快地衰减。借助于能送出中空的锥形射流的喷嘴,可以满足上述要求。在射流的空腔内部和外部空间中,有逆向补充气流形成。人们曾经对不交汇的锥形射流的射流特性进行了研究。本文的目的在于描述交汇射流的轨迹和确定射流本身和内部逆向气流的速度值。在射流流出的方向上作用着两个力:射流的初始冲力I_o(图1 α)和内外空间的静压(P_B和P_H)差。如果认为冲力在射流的内外空间中均匀分配,则根据动量方程可确定这两个力的值:
When the amount of air sent from the air outlet close to the work area is large, it is necessary to make the speed of the jet and the temperature difference between the jet and the ambient air decay as quickly as possible. The above requirement can be satisfied by means of a nozzle that can deliver a hollow conical jet. In the interior of the cavity of the jet and in the outer space, there is an inverse supplemental flow formation. People have studied the jet characteristics of conical jets that do not meet. The purpose of this paper is to describe the trajectory of the convergent jet and to determine the velocity values of the jet itself and the internal counter-current. Two forces act in the direction of the outflow of the jet: the initial impulse I_o of the jet (Fig. 1 α) and the static pressure (P_B and P_H) of the interior and exterior spaces. If the impulse is thought to be evenly distributed in the inner and outer space of the jet, the values of these two forces can be determined from the momentum equation: