A DESIGN OF GAS MIXER FOR SYNGAS ENGINE USING THREE-DIMENSIONAL CFD MODELING.

A gas mixer prototype is developed for mixing air and synthesis gas or “syngas” as a fuel. Syngas is being recognized as a viable energy source worldwide, particularly for stationary power generation. Syngas has a very low energy density, so a mixer with λ (ratio of actual to stoichiometric air-fuel ratio) in the range of 1.1 to 1.7 is expected. In this study, three-dimensional computational fluid dynamics (CFD) modeling is used to design venturi mixer, coaxial mixer and coaxial mixer with vortex generator. CFD modeling is used to investigate and analyze the influence of the throat diameter, gas chamber thickness and gas exits diameter on mixer characteristics and performance of the venturi mixer. While on the coaxial mixer model, CFD is used to analyze the influences of the primary nozzle exit diameter, constant pressure mixing chamber geometry, constant area mixing chamber geometry, divergent passage geometry, syngas inlet position and primary nozzle exit position on the coaxial mixer characteristics and performance. To design appropriate vortex generator, computational models are used to analyze the influence of the mechanical tab angle, number of tabs and geometry on the mixing characteristics and performance of the coaxial mixer. Attention is focused on the effect of mixers and vortex generator tabs geometry on the air-fuel ratio, pressure loss and mixing quality. Based on the numerical results, an optimized design of venturi gas mixer, coaxial mixer and vortex generator is decided and made. The optimized design of the venturi mixer has λ in the range of 1.2 to 1.3, good mixing quality and pressure loss of 46 Pa on air flow rate 100 m 3 /h. The optimized design of the coaxial mixer has λ ranging from 1.1 to 1.7 corresponding to pressure losses from 28 to 19 Pa at 100 m 3 /h air-flow rate. The optimized design of coaxial mixer equipped with the proposed vortex generator has λ in the range of 1.1 to 1.7 corresponding to pressure loss in the range of 41.4 to 31.9 Pa at 100 m 3 /h air flow rate. At λ about 1.2 and 100 m 3 /h air flow rate, the mixing quality of the optimized venturi mixer, coaxial mixer and coaxial mixer equipped with vortex generator have coefficient of variation (CoV) of 0.67, 0.88 and 0.29 respectively

STUDI EKPERIMENTAL PENGARUH JUMLAH SUDU TERHADAP UNJUK KERJA TURBIN ANGIN CROSSFLOW

Wind energy is a potential natural resource that is abundant and clean so that it can be used to answer the problem of the crisis of non-fossil energy sources. The tool that can be used to convert the kinetic energy of the wind into electrical energy is a wind turbine. Crossflow wind turbines are one of the modified VAWT types from banki water turbines. Cross-flow wind turbines have a simple design, high torque coefficient at low tip speed ratio, good self starting, not noisy and more stable so that it is suitable for application in urban areas. To obtain a cross-flow wind turbine with good performance, several design parameters must be considered. The parameter number of blades is an interesting concern for the development of the design of cross-flow wind turbines. This experimental test aims to find the highest rotation of variations in the number of crossflow blades. Variations in the number of blades are 16, 20 and 24. Each variation of blade number is tested with 5 different wind speeds, namely 4.99 m / s, 5.94 m / s, 6.49 m / s, 6.99 m / s and 7.27 m / s. The test results show that the highest rotation speed is obtained in wind turbines with a number of blades 20 at a wind speed of 7.27 m / s. the highest rotation speed is 250 rpm

Analisis statistik performa turbin angin vertikal dengan slotted blades

Energi terbarukan merupakan energi alternatif yang bersih, bebas polusi, aman dan ketersediaanya tidak terbatas. Energi angin merupakan salah satu energi terbarukan. Pemanfaatan energi angin dilakukan dengan menggunakan turbin angin salah satunya savonius. Turbin savonius memiliki kekurangan pada nilai koefisien daya (Cp) yang rendah. Penambahan konfigurasi posisi dan lokasi slotted blades dapat meningkatkan nilai Cp. Untuk memaksimalkan desain turbin angin savonius maka perlu dicari faktor yang paling berpengaruh terhadap nilai Cp. Penelitian ini bertujuan untuk menganalisis signifikansi unjuk kerja turbin angin savonius dengan konfigurasi slotted blades secara statistik. Pengujian hipotesis dari dua faktor yang mempengaruhi nilai Cp dilakukan dengan menggunakan metode pengujian statistik Kolmogorov Smirnov Test, Normalitas test, analysis-of-variance (ANOVA) linier, one-way ANOVA menggunakan software SPSS 22. Hasilnya menunjukkan bahwa lokasi slotted blades berpengaruh secara signifikan terhadap nilai Cp (Sig. 0,000 kurang dari 0,05). Terdapat interaksi antara kedua variabel uji posisi*lebar (Sig. 0,000 kurang dari 0,05). Posisi slotted blades lebih berpengaruh signifikan terhadap nilai Cp karena nilai Sig. 0,000 lebih rendah dari lebar slotted blades 0,01

STUDI EKSPERIMENTAL PENGARUH ASPEK RASIO TERHADAP UNJUK KERJA TURBIN ANGIN CROSSFLOW

Wind energy has been referred to as one of the primary renewable energy sources since 2000. Its axis-based concrete wind turbines are horizontal wind turbines (HAWT) and vertical wind turbines (VAWT). VAWT are generally in urban areas with an average speed that is relatively small and its direction is variable. VAWT is divided into several types, namely Savonius and Darrieus turbines. Cross-flow wind turbines derived from the concept of banki water turbines can be an alternative to extract potential wind energy into electrical energy. Cross-flow turbines have a simple design. Can be used and can produce high torque at relatively low speeds. Many designs of geometry design in cross-flow with the aim of improving the performance of the turbine. The aspect ratio (H / D) is one of the parameters that can affect the performance of a crossflow wind turbine. This ratio is used to measure the crossflow ratio aspect. Variation in aspect ratio (H / D) which is 1, 1.56 and 0.64 with number of blades 16. If the number of blades is carried out with 5 different wind speeds of 4.99 m/s, 5.94 m/s, 6.49 m/s, 6.99 m/s and 7.27 m/s. The experimental results show the highest speed in the wind turbine with an aspect ratio (H / D) of 1.56 at a wind speed of 7.27 m/s. The highest rotation speed is 313 rpm

Indirect Liquid Cooling for Battery Thermal Management: A Review

The thermal management system of batteries is a critical aspect of battery management for optimizing battery performance and lifespan. Research has rapidly progressed in battery thermal management in the past decade, mainly by adopting indirect liquid cooling methods. This article provides an in-depth overview of the recent developments in indirect liquid cooling application for battery thermal management, encompassing fundamental principles, types of fluids, and the strengths and weaknesses of this method. Various heat transfer techniques, such as convective heat transfer and heat generation, are also examined to comprehend effective ways of precisely managing battery temperature. The benefits and challenges of this indirect liquid cooling approach are evaluated, considering crucial criteria like safety. The results of this review demonstrate that the indirect liquid cooling method holds promise as an effective solution to address thermal challenges in batteries, with the potential to enhance overall battery performance and durabilit

SIMULASI HORIZONTAL AXIS WATER TURBINE TIPE SAVONIUS PADA ALIRAN AIR DALAM PIPA MENGGUNAKAN APLIKASI SOLID WORK

The potential energy available in the abundant water in Indonesia can be used as electrical energy resources such as pico hydro. Savonius turbines installed at picohydro power plant contained in the flow of water in the pipe. This study uses a turbine that has angle of attack of 80°, 90°, 100°, 110°, the blade number of 2, 4, 6, 8, and blocking angle system of 20°, 30°, 40° and 50°. SolidWorks software is used to perform modeling and simulation in the Savonius turbine. Computational Fluid Design (CFD) is used to design analysis of the turbine. The obtained results are pressure distribution on the Savonius turbine blade, water flow and torque generated. The aims of this study are to obtain the best performance of the turbine design as pico hydro power plants (PLTPH). The results show that the blade number of 2 with the angle of attack about 80° and deflector angle of 50° have the highest torque about 1,766 Nm. Keywords: Savonius turbine, variation, torque, simulation, SolidWorks fluid flo

ANALYSIS OF ADDITION THE NUMBER OF HALF CIRCLE TYPE SLOT ON PERFORMANCE CHARACTERISTICS OF DISC CONDUCTOR EDDY CURRENT BRAKE

Brake is a vital component of a vehicle, particularly for motor vehicles. One of the braking used the principle of Eddy Current Brake by utilizing electromagnetic. Eddy Current Brake is a braking technology without direct contact by utilizing eddy currents. Eddy Current Brake performance can be influenced by several factors, one of them is the surface shape of the disc conductor. Using finite element simulation, this research examines the impact of increasing the number of slot half-circles on the performance of the Eddy Current Brake with the number of slot changes. Variations number of slots that used are 6, 8, 10, and 12 slots. The result of this study obtained the best braking torque value in the variation with the number of 10 slots at a rotational speed of 450 rpm with a 15,930 Nm torque value. The addition slots of the number of half-circle types have a less significant effect on the torque from the simulation

SLOW PYROLYSIS OF SELECTED AGRICULTURAL WASTES: ANALYSIS OF THERMAL DEGRADATION BEHAVIOR

The use of fossil fuels produces carbon dioxide (CO2).  Carbon dioxide is one of the greenhouse gasses that contributes to global climate change. Due to this issue, there is increasing the requirement for the use of renewable materials and development of the additional sustainable process. Agricultural waste that has the property of fast growth, is an alternative renewable energy. In this work the slow pyrolysis of selected agricultural wastes mixture (cassava peel-rice straw, rice straw-rice husk, and cassava peel-rice husk) were studied to determine thermal degradation behavior of the biomass. The process was conducted in a fixed bed reactor at temperatures 325 °C, at 10 °C/min heating rate and at 10 min holding time. Results revealed that the moisture content of agricultural wastes were 4.40 % (cassava peel-rice husk), 5.48 % (rice straw-rice husk) and 8.12 %  (cassava peel-rice straw). The devolatilization process of the biomass was taken place in the temperature range from 189 oC to 325 oC. The volatile matter of each sample was 61.5%  for cassava peel-rice husk, 58.5 %  for rice straw-rice husk and 52.5 % for cassava peel-rice straw

WAHANA PAPAN SELUNCUR SEBAGAI SARANA INTERAKSI ANAK DENGAN DUNIA LUAR

Abstrak: Taman bermain merupakan lingkungan yang dirancang khusus untuk menyediakan kesempatan bermain, belajar, dan berinteraksi bagi anak-anak. Taman bermain tidak hanya merupakan tempat hiburan semata, tetapi juga berperan sebagai ruang pendidikan yang mendukung perkembangan fisik, kognitif, sosial, dan emosional anak-anak. Pengabdian ini bertujuan untuk merancang desain wahana bermain papan seluncur yang dirancang dengan mempertimbangkan faktor keselamatan, kenyamanan, dan pengembangan anak di Taman Mekarsari Desa Kaligentong, Kecamatan Gladagsari, Kabupaten Boyolali. Papan seluncur merupakan sebuah wahana dengan bentuk seperti seluncuran yang difungsikan sebagai sarana anak-anak untuk berinteraksi pada lingkungan luar. Metode yang digunakan pada pengabdian ini berupa deskriptif kualitatif yang dilakukan melalui tahapan wawancara dan observasi. Pengabdian ini merupakan kolaborasi antara dosen dan mahasiswa Program Studi Teknik Mesin, Universitas Sebelas Maret, Surakarta dengan Kelompok Tani (PokTan) Desa Kaligentong, Gladagsari, Boyolali sebagai pengelola Taman Mekarsari. Evaluasi yang dilakukan untuk wahana bermain ini yaitu dengan melakukan simulasi percobaan papan seluncur secara langsung. Dari kolaborasi ini didapatkan hasil berupa desain papan seluncur yang kokoh dan dibuatnya wahana bermain papan seluncur yang aman dan nyaman di Taman Mekarsari. Diharapkan dengan adanya wahana bermain ini dapat mendorong interaksi sosial dan pengembangan keterampilan anak-anak sehingga dapat meningkatkan kualitas hidup dengan memberikan kesempatan bermain dan belajar secara menyeluruh.Abstract:  Playgrounds are environments specifically designed to provide opportunities for children to play, learn and interact. Playgrounds are not only places of entertainment, but also act as educational spaces that support children's physical, cognitive, social, and emotional development. This service aims to design a skateboard playground that is designed by considering safety, comfort, and child development factors at Mekarsari Park, Kaligentong Village, Gladagsari District, Boyolali Regency. Papan seluncur is a vehicle with a shape like a slide that functions as a means for children to interact with the outside environment. The method used in this service is descriptive qualitative which is carried out through interviews and observations. This service is a collaboration between lecturers and students of the Mechanical Engineering, Universitas Sebelas Maret, Surakarta with the Farmer Group (PokTan) of Kaligentong Village, Gladagsari, Boyolali as the manager of Mekarsari Park. The evaluation carried out for this playground is by simulating the papan seluncur experiment directly. From this collaboration, the results were obtained in the form of a sturdy papan seluncur design and the creation of a safe and comfortable papan seluncur playground in Mekarsari Park. It is hoped that this playground can encourage social interaction and skill development of children to improve the quality of life by providing comprehensive play and learning opportunities. 

Axial Unipolar Eddy Current Brake Performance Characteristics Against Heat Increase in Rotor

The development of transportation technology in the automotive sector such as electric vehicles is increasingly advanced. One technology that is needed quite a lot is the development of supporting technology for electric vehicle braking. The use of regenerative braking on light electric vehicles such as 2-wheeled vehicles is not efficient because of its low weight. The use of Eddy Current Brake (ECB) can be a solution for braking support needs. This is because the ECB is a braking system that has the advantage of a lightweight design but still relies on the frictionless principle. However, in addition to its advantages, the eddy current brake is still in the early stages of its research with efficiency that still needs to be developed. In the discussion of the ECB, heat generation is one of the interesting topics to be discussed. Specifically, the study of the characteristics of the unipolar ECB axial performance on heat generation events has not yet been discussed. So this article aims to discuss these events with a simulation process and simple mathematical calculations. Design optimization is done to get the best value. As a result, the use of eddy current brakes with conductor disks using slots, can improve the performance of the ECB on the torque side and cooling side. Thus, this article is a good contribution to the sustainability of ECB research in both the general and automotive fields