A Steam Ejector Refrigeration System Powered by Engine Combustion Waste Heat: Part 1. Characterization of the Internal Flow Structure

Abstract

With the escalating production of automobiles, energy efficiency and environmental friendliness have always been a major concern in the automotive industry. In order to effectively lower the energy consumption of a vehicle, it is essential to develop air-conditioning systems that can make good use of combustion waste heat. Ejector refrigeration systems have become increasingly popular for this purpose due to their energy efficiency and ability to recycle waste heat. In this article, the elements affecting the performance of a typical ejector refrigeration system have been explored using both experimental and numerical approaches. For the first time, the internal flow structure was characterized by means of comprehensive numerical simulations. In essence, three major sections of the steam ejector were investigated. Two energy processes and the shock-mixing layer were defined and analyzed. The results indicated that the length of the choking zone directly affects the entertainment ratio under different primary fluid temperature. The optimum enterainment ratio was achieved with 138 °C primary fluid temperature. The shock-mixing layer was greatly affected by secondary fluid temperature. With increasing of back pressure, the normal shock gradually shifted from the diffuser towards the throat, while the shock train length remains lunchanged.

A novel thermal management system for battery packs in hybrid electrical vehicles utilising waste heat recovery

“…It was found that when the nozzle exit position is fixed, the ejector's COP is positively related to the diameter of the constant section. Han et al studied the internal flow structure [28] and shock waves [29] inside a steam ejector powered by engine combustion waste heat. It was found that the internal flow structure, such as the pseudoshock region and normal shock position, can affect the entrainment ratio.…”

Optimum Efficiency of a Steam Ejector for Fire Suppression Based on the Variable Mixing Section Diameter

“…However, in the aspect of experimental study, the experimental study of the ejector is insufficient. Han et al reported the structure of the internal steam ejector flow [ 18 ] and shock wave [ 19 ] driven rejected combustion engine heat source. The research revealed the potential effect of the internal structure flow on the entrainment ratio (determined as the ratio between the suction and the motive nozzle mass flow rates), mainly the location of the normal shock and the pseudo-shock region.…”

Optimisation Analysis of Structural Parameters of an Annular Slot Ejector Based on the Coanda Effect

“…An annular slot ejector is a mechanical device which is different from a central jet [1][2][3][4]. A large volume of lowpressure fluid is dragged by high-pressure fluid due to the special structure of the annular slot ejector [5].…”