No abstract

Proses pengeringan menggunakan pengering surya ultraviolet berupa pengering efek rumah kaca memiliki biaya operasional yang relatif rendah, sehingga berpotensi untuk dikembangkan dalam teknologi pengeringan pangan. Penelitian ini bertujuan untuk menguji parameter kinetik pengering daun kelor melalui variasi kecepatan udara keluar dari rumah pengering. Berat daun kelor yang akan dikeringkan dibagi rata ke dalam tiga rak pengering di rumah pengering dengan beban pengeringan yang sama yaitu 4,76 kg/m2. Hasil penelitian menunjukkan bahwa dengan variasi kecepatan keluar yaitu 0,5 m/s, 1,0 m/s, dan 1,36 m/s kekurangan energi panas yang cukup untuk mengubah mekanisme perpindahan panas konveksi pada pengering menjadi konveksi paksa. Sedangkan efisiensi pengeringan meningkat dengan bertambahnya kecepatan aliran keluar, karena kondisi saluran masuk yang tidak diatur sehingga aliran udara masuk yang membawa uap air (terutama saat mendung) meningkatkan kelembaban udara di dalam pengering. perumahan termasuk kadar air bahan dan secara bersamaan mengurangi laju pengeringan dan efisiensi rumah pengering.The drying process using an ultraviolet solar dryer in the form of a greenhouse effect dryer has relatively low operating costs, so it has the potential to be developed in food drying technology. This study aims to test the kinetic parameters of the Moringa leaf dryer through variations in air velocity leaving the dryer house. The weight of the Moringa leaves to be dried is divided evenly into three drying racks in the drying house with the same drying load, which is 4.76 kg/m2. The results showed that with variations in the exit velocity, namely 0.5 m/s, 1.0 m/s, and 1.36 m/s, they lacked sufficient thermal energy to change the convection heat transfer mechanism in the dryer into forced convection. While the drying efficiency increases with the increase in the velocity of the outflow, due to the condition of the inlet that is not regulated so that the inlet airflow carrying water vapor (especially when it is cloudy) increases the humidity of the air in the dryer housing including the moisture content of the material and simultaneously reduces the drying rate and efficiency of the dryer housing.

Numerical analysis was conducted on the aerodynamic performance and the flow characteristics around the counter-rotating wind turbine or CRWT blade through rear rotor configuration using various rotor diameter ratios and distance ratios to the turbine blade through a CFD (Computational Fluid Dynamics) simulation. CFD simulation showed the normalized power coefficients of the front rotor, rear rotor, and combined rotor (CRWT) to the single rotor with a strong influence of the rear rotor configuration with the addition of tip speed ratio (TSR). A larger average normalized power coefficient takes place at D1/D2=1.0 with L/D1=0.75 by 1.221. It is about 22.1% increased to the SRWT for the given TSR range. Axial velocity contours and resultant velocity vectors around the CRWT blade with a diameter ratio of D1/D2 > 1.0 and a closer rotor distance provide a stronger bound vortex and strong separation around the rear hub blade with a tendency to increase from the hub to the tip blade at low TSR. The higher the TSR, the movement of tip vortex moves closer to the rear tip blade which has the effect of increasing the leakage flow in the area of D1/D2 < 1.0.