Performance Analysis And Process Investigation On The Adjustable Ejector

Ejector is applied broadly in different kinds of fluid machinery, which uses working fluid to achieve heat and mass transfer. Ejector is energy-saving, less pollution, as well as simple construction and low cost and maintenance, so it is very popular in industrial fields.The complex of the flow inside ejector makes it difficult to have a better understanding. Conventional ejector must be designed to match the system operating conditions accurately, otherwise either the efficiency will be impaired or it will not work at all. The limited operating range of ejector restricts application on industries. Therefore, the research on ejectors is important to industry energy-saving and environment-protecting.In this paper, a novel adjustable ejector was brought out. A spindle moving into or out of nozzle axially changed nozzle throat area, which made the adjustable ejector different from conventional one. Experimental and numerical simulations were utilized to analysis connections between the positions of adjustable nozzle spindle and ejector performance parameters. The results indicated that the adjustable ejector, compared to conventional ejectors, could improve the efficiency caused by working parameters' deviation from design point and widen the operating range.The main work and results of this paper are given as follows:(1) The blue print of the adjustable ejector was designed. Programs were compiled to analyze the effects of operating parameters, such as pressures, flow rates and entrainment ratio, on adjustable ejector performance. The results showed that the entrainment ratio rised and motive flow rate droped when nozzle throat area decreased.(2) 2-D axial symmetry model was set up to simulate adjustable ejector flow by Flunet. The static pressure, static temperature and velocity of adjustable ejector were displayed to compare that of conventional fixed-geometry ejector at the same working condition. The conclusion was that the nozzle exit velocity and ejector efficiency increased and mixed flow turbulence weakened with spindle moving into nozzle.(3) An adjustable ejector experiment apparatus was established with valves, pipes, fanges and metrical instruments. The working condition of adjustable ejector was recorded to measure pressures, temperatures and flow rates of motive fluid, suction fluid and discharge fluid. It revealed that the adjustable ejector owned relatively stable working condition on off-design point, although the entrainment ratio was not high. This makes adjustable ejector superior to conventional one and meets variational and economic demands of operating condition.