Numerical Simulation Of Multipie Thermal Water Buoyant Jets In The Near Field In Coflow

Buoyant jet as a kind of common flow in nature exists widely in various industries. The theory and technology of buoyant jet is applied in lots of engineering technology fields.Therefore,the research of buoyant jet is of importance significance not only for academic, but also for practice. A amount of work has been done on the study of single jet and jet in static water,but the study on multiple buoyant jets in flowing water is seldom seen.So,in this article we will study the multiple buoyant jets in coflow using numerical simulation.Discussing the mixing characteristics and their changes law of all kinds of characteristic quantities by calculating use Reyonlds model in FLUENT software and SIMPLE algorithm.In this article we review the basic theories of jet firstly.we also give the status analysis of jet and summarize simply the study works of many experts and scholars both at home and abroad.Secondly we introduces the turbulence mathematical model. The basic hypotheses and equations of turbulence mathematical model are expounded.All turbulence mathematical models we have classified are compared,and their advantages and disadvantages are given.Then the turbulence numerical simulation method is introduced.The numerical discrete methods and discrete scheme are summarized.We also introduce the SIMPLE algorithm and discrete processes of one-dimensional, two-dimensional and three-dimensional control equations.The three software we used in this paper are introduced in brief.We firstly calculat different jets in coflow by numerical simulation.The pressure field, velocity field and temperature field at different jets are given. We obtain the main difference between single jet and multiple jets is that there is Candida effect between two adjacent jets.At the same position from jet exit section ,The jets more,the bigger the value of all characteristic quantities.As the following, the mixing characteristics of all characteristic quantities at different spacing are analyzed taking three jets as an example. We get the simple that the spacing is bigger, the mixing point is farther, the Candida effect is less obvious, and the value of all characteristic quantities at the same position from jet exit section is smaller.Then we get the flow field and temperature field at different jet temperature.We obtain that the higher the jet temperature,the bigger the buoyant efffect,and the temperature at the same position from jet exit section.At last, we simulat the thermal water buoyant jets in coflow at different velocity ratio.We know that the bigger the velocity ratio,the less obvious the buoyant effect,and the laeger the area that closed by isovel,and the laeger the area effect by high temperature.The jet's trochoids are also given.Finally, all the work and fruits in the paper are summarized and the defects and further work are elaborated.