|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|154800||2017||22 صفحه PDF||سفارش دهید||8976 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : International Journal of Refrigeration, Available online 31 October 2017
CO2 two-phase ejectors are used as expansion work recovery components in refrigeration or heat pump systems. A new thermodynamic model is developed for both single choking and double choking conditions to design such ejectors and investigate their performances. This model, based on the homogeneous equilibrium model (HEM), solves the conservation equations using real fluid properties rather than ideal gas assumptions. The irreversibilities due to friction in the nozzles and the diffuser are accounted for by polytropic efficiencies. The performance of a two-phase ejector is predicted for a fixed ejector geometry and given inlet operating specifications at off-design conditions. The model can also evaluate the ejector dimensions for given inlet and outlet operating conditions (on-design). The results are compared and validated against published experimental data. The effects of the irreversibilities on the ejector dimensions are investigated in detail.