Studi eksperimen kinerja turbin vortex berbasis gravitasi dengan sudu backward dan forward

Nowadays, the use of hydro energy in Indonesia is still focused on large-scale hydropower development which has negative effects on the environment such as changes in the natural flow of rivers, disruption of the population of aquatic biota that live in these watersheds and has the risk of potential disasters if the dam fails. In fact, the energy potential from the mini-micro hydro source is 19,835 MW, but its utilization is still very low around 100 MW. Therefore, the extraction of water flow energy in the form of rivers and irrigation channels with very low head altitude differences is considered important and urgent so that a gravity vortex turbine-based mini / micro hydro research is proposed. Specifically, this study aims to analyze the performance of the vortex turbine with backward and forward blades in a conical basin through laboratory experimental devices. Experiments were carried out on a fluid flow rate of 120 liters per minute (lpm) and 100 lpm by loading using a prony brake dynamometer in order to obtain torque performance data on variations in turbine blade rotational speed. In this experiment, the results showed that the performance of the backward blade turbine was superior with its optimal efficiency reaching 36.7% at a discharge of 120 lpm and a rotating speed of 80 rpm than the forward blade which at a discharge of 120 lpm and a rotating speed of 80 rpm was only able to achieve its highest efficiency at 33.19%.

Analysis of cross-sectional area of digester on biogas production rate

Biogas has become one of the promising alternative fuels. This is triggered by relative ease of production while on the other hand the raw material is cheap and easy to be obtained. In order to get higher biogas production rate, a work has been done with digester cross-sectional area modification. Under the modification an improvement in biogas yield was obtained. The research also has opened up new outlook to set up a better digester design for maximum biogas production. The experimental results showed that a higher biogas volume yield was obtained in larger cross-sectional area compared to that of smaller one. Increasing the cross-sectional area twice will benefit at least three times in terms of biogas volume produced under similar raw material input volume. A wide-open cross-section surface is a major factor for good breeding of microbial to produce methane. Under the condition, microbes experience less pressure due to the evenly distributed volume of the substrate which resulted in a comfortable environment for bacteria.

Sampul Dinamika Teknik Mesin, Vol. 11, No. 1, April 2021

Sampul Dinamika Teknik Mesin, Vol. 11, No. 1, April 2021

Optimasi parameter resistance spot welding pada pengabungan baja electro-galvanized menggunakan metode Taguchi

The present study features analytical and experimental results of optimizing resistance spot welding performed using a pneumatic (electrode) force system (PFS). This optimization was carried out to incorporate the galvanized steel sheet material SECC-AF (JIS G 3313) and SPCC-SD (JIS 3141) sheet plate coated with zinc with a thickness of about 2.5 microns. The zinc coating on the metal surface causes its weldability to decrease. This study aims to obtain the highest tensile shear strength test results from the combination of the specified resistance spot welding parameters. The research method used the Taguchi method using four variables and a combination of experimental tingkats. This study's experimental tingkat is two tingkats in the first parameter and three tingkats in other parameters. Taguchi optimization results show that the highest tensile shear strength test obtained is 5049.64 N. This was achieved at 22 cycles of squeeze time, 25 kA of welding current, and 0,6-second welding-time, and 12 cycles of holding-time. The S / N ratio analysis found that the welding time had the most significant effect, followed by welding current, holding time, and squeeze time. The delta S / N ratio values were 0.62, 0,41, 0.34 and 0.07, respectively.

Rancang bangun dan uji performansi mesin pencampur beberuk, makanan khas Lombok

During this time the process of making beberuk was still done traditionally using a mortar as a mixer, so that production is very limited, while the market demand is quite high. To increase productivity, it is necessary to design a machine that can increase the production capacity of the beberuk. The research method begins with the mixing machine design process, then continues with the assembly process and engine performance test. The design of the mixing machine is done with two approaches namely functional approach and structural approach. Test engine performance on 3 power variations namely 144, 168, and 192 watts and 3-time variations namely 30, 45, and 60 seconds. The results showed that the cylindrical mixing chamber has a diameter of 20 cm and a height of 50 cm. The mixing tube has a rectangular hopper with dimensions of 37 cm long and 9 cm wide. Engine performance test results showed the best results on 168 watts of power treatment and 30 seconds with the results of mixing not bubbly and still looks tomato chunks and is not too smooth according to the standard beberuk food.