Jurnal Internasional


Syamsuri and Suheni
Department of Mechanical Engineering, Adhi Tama Institute of Technology Surabaya, Indonesia
E-Mail: [email protected]

The increase in energy demand caused by population growth and resource depletion of oil reserves as well as the
problems of emissions from fossil fuels put pressure on every country, especially Indonesia. Briquettes of corncob were one of the alternatives. In addition replaced the firewood, they also did not potentially damage the ecology of the forest and could replace fossil fuel reserves that were running low. Water boiling test was used to determine the performance of a portable stove with and without fin. Inside the stove there were 3 pots: pot 1 contained egg, pot 2 contained of rice, and pot 3 was vegetables. This study was obtained for the power of furnace for different diameter of briquette 3/4 “, 1” and 1.5” without fins was equal to 0.87 kW, 1.12 kW and 1.57 kW, respectively. Efficiency 17.58%, 19.7%, and 23.15%. While the furnace with diameter briquette 3/4 “, 1” and 1.5” using fins obtained the power 0.98 kW, 1.32 kW and 1.96 KW. Efficiency 14.84%, 20.91% and 25.27%. The fastest cooking time was gained for the finned pan with diameter of briquettes 1.5” over 20 minutes.

Keywords: briquettes, corncob, portable furnaces fins and without fins.

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Characteristics of Decompression Tank Internally Pressurized With Water Using OpenFOAM


Mechanical Engineering Department, ITATS Surabaya, Indonesia

email: [email protected]

Keywords: Decompression tank, OpenFOAM, Variation of compressibility water.


Decompression tank is a tank in which pressurized with water. In its application decompression tank can be reservoir tank and water storage tanks which are closed. In the simulation the value of compressibility is very important for the case decompression tank. The method used is the numerical simulations using OpenFOAM software to know the results of observation the value of the pressure, density, and velocity magnitude.

Simulations will be performed by varying the value of the water compressibility 4.54e-06 4.54e-07, and 4.54e-08. Before performing simulations on the main case decompression tank then first performed by grid independent test to validate the simulation results from the study by another researcher. From the results of experiments with variation of compressibility of water it can be seen that a good comparisons with numerical simulation and previous studies show the capability of this method. The greater the value compressibility water then the pressure distribution generated more widely and rapidly spreadas well as the velocity distribution. However for the distribution of the speed with greater compressibility of the velocity distribution will become more varied and occurs only in a small area.

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Flow Characteristics Across a Cavity with Variation of Reynolds Using OpenFOAM

Syamsuri*, Dwi Khusna

*Email:[email protected]

Department of Mechanical Engineering, Institut Teknologi Adhi Tama Surabaya, Indonesia
Developments in science and technology had prompted us to conduct various experiments to create a variety of things, which aims to facilitate and provide benefits for humans and beneficial to the continuation of the next study. Fluid flow across alid-driven cavity was one of the important phenomena in the fields of engineering, especially fluid mechanics. Somereal casesuch as the air flow in a room was an example of the occurrence of this flow. The method used was numerical simulations using OpenFOAM software to determine the value of the observation of the pressure distribution on the outer and inner wall (2D).
Variations of Reynolds numbers used were 40, 100 and 1000. For the kinds of case’s lid-driven cavity was used to provideinformation about the flow phenomena. Further analysis and comparison of the results of the data obtainedin order to obtainlid-driven cavity flow phenomena with the potential of increasing the engine work well. From the simulation data obtained that inthe case of lid-driven cavity for Reynolds numbers 40 obtained a value of 1.4079 Pa pressure distribution, which causes theformation of eddy (vortex). At Reynold’s number of 100 obtained values of 0.738674 Pa pressure distribution which causes theformation of such eddy Reynold’s number 40. While at Reynolds numbers 1000 led to declining value of the pressure distributionis equal to 0.226075 Pa. There was an interesting phenomenon, with the increasing of Re the vortex which formed higher and more to the center. Vortexb area also greater.
Keywords :
Lid Driven Cavity, Reynolds Number, OpenFOAM, Vortex

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Gati Sri Utami
Department of Civil Engineering, Institut Teknologi Adhi Tama Surabaya, Indonesia
E-Mail: [email protected]
Lapindo mud containing silicate (SiO2) that can function as a filler and lime (CaO ) as a binder between the particles . Previous research in the use of these materials, may be used as, a substitute material of cement, to mix concrete manufacture. While in this study, Lapindo mud is used as, a substitute material lime to stabilize clay soils containing salt. Soil samples were taken from the area Sumenep then mixed with mud Lapindo 10%, 20%, 30%, 40%, 50%. Results of this study, up to 50% concentration slurry liquid limit value decreased 16.67 % and plasticity index, 73.73 % decline of the native land. Test compaction up with a mixture of 40%, the solid based on the increase of the value of γdmax, γdmax
native land at 1.42 kg / cm3 be 1:56 kg / cm3, which means an increase of 11.43%. CBR test up to 30% Lapindo mud mixture , 9.02% CBR value is including the category of value CBR is good enough as a land base and an increase of 44.55
% from the original soil . Direct shear test Lapindo mud up to levels of 40%, the value of the shear stress increased by 40.25% of the original soil. Free press test until the Lapindo mud levels of 40%, the value of free compressive stress 2.03kg / cm2 very rigid categories and an increase of 39.04% from the original soil. And to test free swelling up to levels of 50% Lapindo mud, with a 24 -hour immersion, the value of development decreased by 63.64%. So in general it can be said that the levels of Lapindo mud more than 50% effective in stabilizing the clay in Sumenep area to reduce the potential for
development, while raising the level of Lapindo mud carrying capacity is a maximum of 40%.
Keywords: lapindo mud, stabilization, salt, expands, carrying capacity

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Gati Sri Utami
Department of Civil Engineering, Adhi Tama Institute of Technology Surabaya, Indonesia
E-Mail: [email protected]
Subgrade was a very important part to support all construction loads on it. If the clay subgrade that had
unfavorable properties, such as low CBR, the high swelling when applied to the construction of the road subgrade soil would produce a soil that is easily damaged. For that, if used in the construction of CBR value should be towering so that it can withstand a load on it. The swelling would reduce the volume of soil that is stable when it rains the soil is not swollen, otherwise when the dry season does not shrink too high. Ground improvement methods used in this study was stabilization of lime-soil, using a mixture of percentage 5%, 10% and 15% of the lime. Tests performed on the Atterberg
limits, Compaction (Standard Proctor Test), C.B.R laboratory, and Swelling. The results of the study about a large percentage of the value of lime plasticity (liquid limit, plasticity index) decreased with the increasing compaction. The average CBR value is increased for the natural soil to percentage 5% and 10% of lime, while the percentage of 15% decreased. For the swelling, the percentage of 15% lime with 24 hours immersion showed 45.28% increase in swelling of
the normal soil (i.e. 31.67% to 17.33%) So in general the best for clay soil stabilization is Pakuwon area where the addition of 10% lime CBR values obtained optimum and could reduce swelling value.
Keywords: lime, stabilization, CBR, swelling.

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