با توجه به رشد جمعیت و از طرفی افزایش روز افزون مصرف منابع انرژی در شاخه های گوناگون خانگی و صنعتی و همچنین با توجه به محدودیت منابع انرژی تجدیدناپذیر، ناگزیر به کاهش و اصلاح مصرف انرژی هستیم. ب. تجزیه و تحلیل پینچ یک فرایند صنعتی، برای مشخص کردن هزینه انرژی و هزینه اصلی شبکه تبادلگرهای حرارتی و همچنین تعیین نقطه پینچ بکار می رود. محاسبات اقتصادی مربوط به هزینه های عملیاتی(انرژی) و هزینه کل انجام گردید. با اصلاح شبکه مبدل حرارتی فوق (طراحی رتروفیت) و با میزان سرمایه اولیه 104×1.7 دلار، سالانه 31492 دلار بابت صرفه جویی در مصرف انرژی، عاید سازمان مربوطه می‌گردد. دوره بازگشت سرمایه 180 روز(کمتر از یک سال) به دست آمد. پرونده مقاله

this study investigates the flow separation region on NACA 0012 airfoil at a constant Reynolds number using plasma actuators to create a net body force, and therefore controlling the airflow around rigid objects. These actuators are among the most popular methods in active flow control due to their easy installation, very short response time, and very low power consumption. The K-ω SST turbulence model has been used for simulation and numerical analysis of airflow on the airfoil. The lift coefficients are analyzed and investigated from different angles as well as the critical (stall) angle of attack. Obtained results show that with increasing angle of attack, eddy and return flows in the separation region increase and also the lift coefficient at the stall angle decreases sharply, therefore is causing energy loss. The aim of this study is to minimize the flow separation region and eddies so that the separated airflow from the airfoil is again smoothed over the airfoil surface using plasma actuator. Plasma actuator is defined as a UDF code in ANSYS Fluent software as a body force on the airfoil. In which the lift coefficient is increased with the activation of the plasma پرونده مقاله

Nowadays the application of plasma actuators has drawn much attention due to the possibility of creating a volumetric force and, therefore, controlling airflow around rigid bodies. These actuators are among common flow control methods because of availability, lack of need for special repairs, very short response time, and low power consumption. The aim of this study is to reduce the flow separation region and delay the stall angle. Therefore, the airflow over a NACA 0012 airfoil and with a Reynolds number of 1.4×10^6 was simulated using Spalart-Allmaras turbulence model. In the first step, the lift coefficients in the plasma-off mode were investigated at different angles. The stall angle of attack was shown to be 15°. Then, the lift coefficients and the stall angle for different Reynolds numbers were compared. In the second step, the plasma (DBD) actuator was defined using UDF code in Ansys Fluent software as the body force exerted on the airfoil. Plasma activation led to an increase in the lift coefficients at different angles compared to the plasma-off mode. Subsequently, it was shown that the plasma actuator minimizes the flow separation area on the airfoil. Defining this actuator at an optimal position at a constant RE of 1.4×10^6 on a NACA 0012 airfoil where flow separation occurs changed the stall angle of the airfoil from 15° under normal conditions to 19°. The results of the lift coefficient with the help of plasma actuators showed that the airflow on the airfoil is well controlled at sensitive attack angles. پرونده مقاله