Numerical Research On The Suction Characteristics Of The Ejector Refrigeration Experimental System

Ejector refrigeration system has many advantages, such as simple structure, no moving parts, high stability and reliability, no mechanical wear in operation process, lower maintenance cost and long service life etc, which widely caused the attention of the researchers. This paper simulates the internal flow field of ejector refrigeration, which takes the steam injector in the designed and build injection refrigeration experiment as the calculation prototype by the software FLUENT. The paper mainly focuses on the difference between two-dimensional model and three-dimensional model under the ideal gas condition, the nozzle in wet steam and ideal gas conditions the difference between the three dimensional simulation, meanwhile researches the influence of different parameters on suction characteristics, which can put forward the theoretical basis for enhancement of the reliability and suction performance.The main work and results of this paper are given as follows:(1) The geometric model is established by choosing the steam injector in the experiment system as calculation prototype.(2) Study the influence factors of the calculation precision, such as the grid partition form of the2d and3d, the wet steam model, the ideal gas model, turbulent model, the numerical solution strategy and so on.(3) The numerical solution of the internal water vapor flow distribution and suction characteristics is done on the different operating conditions through choosing the right turbulent model and the reasonable solution strategy, meanwhile, the result of simulation verifies the applicability and evaluates the calculation accuracy of the theory model by comparing with the experimental data.(4) This paper analyzes the performance of the existing experiment system and puts forward the ideas of structure improvements based on numerical simulation.The above study demonstrates that, in the ideal gas condition, the simulation result is close in the2d and3d models; The difference of the three dimensional simulation of nozzle under the condition of the ideal gas and wet steam is big under the influence of spontaneous phenomenon; The ejector coefficient can be improved by appropriately increasing work steam pressure, choosing outlet pressure below critical back pressure, and choosing suitable temperature of the cooling water, based on the measured data of the experiment platform and simulation, meanwhile the increase of ejector saturated steam temperature can enhance the efficiency of the ejector. The paper analyses some reasons of the ejector coefficient in the experiment is less than simulation value, and puts forward the plan of the experimental structure improvement and the improving direction of the theoretical model, which can provide the reference for the future experiment research of the system performance and the validation and improvment of the theoretical model.