Claim Missing Document
Check
Articles

Found 37 Documents
Search

Pengaruh Rasio Step pada Sudden Enlargement Channel terhadap Heat Flux Kondensasi di Porous Media Praswanto, Djoko Hari; Siswanto, Eko; Hamidi, Nurkholis
Jurnal Rekayasa Mesin Vol 8, No 2 (2017)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (701.996 KB) | DOI: 10.21776/ub.jrm.2017.008.02.4

Abstract

One of the most significant parameter in air conditioning problems is air humidity. A porous media can be used as a heat exchanger component in order to increase the heat transfer performance which is significantly depends on the heat flux values inside of them. To determine the heat flux value, a following test section was modeled in this research. A vapor passed through a channel whereas a particular porous media made of active carbon acted as its heat exchanger media. However, the sudden enlargement at the inlet of channel could affect the homogeneity of temperature distributions and also caused some several turbulencies. The research method is vapor flowed over the porous media for 60 minute with temperature of 300oC.The vapor velocity is varied from 1 m/s to 3 m/s and the step ratio also varied between 0 until 1.66. From the experiment shows the bigger step ratio and vapor velocity results the bigger heat flux and air humidity after passed through the low porous media. Heat transfer was occured in porous media including convection heat transfer with the value of Gr/Re2 smaller than 1.
Analisis Perpindahan Panas pada Saluran Berliku Berpenampang Segi Empat dengan Variasi Clearance Belokan Wahyudi, Slamet; Kurniawan, Aris; Hamidi, Nurkholis
Jurnal Rekayasa Mesin Vol 1, No 1 (2010)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (418.589 KB)

Abstract

Heat transfer characteristics in rectangular with a sharp 180o turn have been examined experimentally using the naphthalene sublimation method. The sharp 180° turn was obtained by dividing a rectangular passage into two channels using a divider wall with a rounded tip at the location where the flow negotiates the turn. The channel cross-section (WxH) is 50×25 m, and three turn clearances of 30, 50, and 70 mm have been tested in this study. Local mass transferrates on all walls of the channel have been measured to clarify the heat transfer characteristics in the channel. The result indicated that the highest coefficient of heat transfer was achieved in the channel with turn clearances of 30 mm.Keywords: Heat Transfer Characteristics in Rectangular,Turn Clearances, Mass Transfers
Studi Inhibisi Formasi Kristal Es dengan Krioprotektan Sukrosa dan Glicerol Hamidi, Nurkholis
Rekayasa Mesin Vol 1, No 1 (2010)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (330.11 KB)

Abstract

A large number of investigations have been carried out to understand the mechanism of freezing and mechanical damages in biological materials. Harmfull ice crystal has been proposed to be a factor causing injury to biological materials during the freezing. How to control,eliminate, or prevent the intracellular ice formation become an important research topic in fundamental cryobiology. Microscopic observation of the freezing process of onion epidermistissue have been made using a solidification stage in order to study the possibility ice crystal formation inhibition using glycerol and sucrose as a cryoprotectant. Experiments conductedunder cooling rates of 40oC/min and 70oC/min. The results indicated that the increasing glycerol can depress the freezing initiation temperature. However, vitrification of onion cells only can beachieved when we used high concentration of cryoprotectant (more than 70%vol sucrose(0.8M)+30%vol glycerol) with relatively rapid freezing (more than 70oC/min).Keywords : ice crystal inhibition, cryoprotectant, glycerol, sucrose
Pengaruh Penambahan Tongkol Jagung Terhadap Performa Pembakaran Bahan Bakar Briket Blotong (Filter Cake) Hamidi, Nurkholis; Wardana, ING; Sasmito, Handono
Jurnal Rekayasa Mesin Vol 2, No 2 (2011)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (209.918 KB)

Abstract

Studies have been carried out on utilizing agricultural wastes of corn cobs to enhance the properties of filter cake briquette. Briquettes of mixtures between filter cake and corn cobs were produced in order to increase the fiber content and reduce the ash content. In this study, the concentrations of corn cobs were varied at 0%, 2%, 6%, 10%, and 15%. The properties of the briquettes were compared. It was found that the burning rate, caloric value, burning temperature and combustion efficiency showed improvement with increase in corn cobs concentration. Keywords : filter cake, corn cobs, combustion performance
Peningkatan Kualitas Bahan Bakar Biogas Melalui Proses Pemurnian Dengan Zeolit Alam Hamidi, Nurkholis; Gede Wardana, I Nyoman; Widhiyanuriyawan, Denny
Jurnal Rekayasa Mesin Vol 2, No 3 (2011)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (150.331 KB)

Abstract

Biogas from digester consists primarily of methan (CH4) and carbondioxyde (CO2). Trace components that are often present in biogas are water vapor (H2O) , hydrogen sulfide (H2S),hydrocarbons (HC), ammonia (NH3, oxygen (O2), carbon monoxide (CO) and nitrogen (N2). In order to improve the quality of biogas, a cleaning process to remove the trace components and an upgrading process to adjust the calorific value are needed. A number of techniques have been developed to remove the trace components from biogas. In this experiment, however, chemical absorption of CO2 and H2S by solid zeolite in a plastic bag was experimentally investigated. The solid zeolite was activated by heat treatment and KOH. Absorption characteristics were examined. Test results revealed that the solid zeolite used were effective in adsorbed CO2 and H2S in biogas, creating CH4 enriched fuel. Absorption capability was transient in nature. With regular replacement or regeneration of used solid zeolite, upgraded biogas can be maintained. This technique proved to be promising in upgrading biogasquality.Keywords: KOH compound, calorific value of biogas, zeolite.
Pengaruh Clamping Frame Kayu Meranti dan ASTM A36 pada Friction Spot Joining AL 1100 dan PVC Raharjo, Rudianto; Hamidi, Nurkholis; Widodo, Teguh Dwi; Bintarto, Redi; Habibulfalah, Endi
Rekayasa Mesin Vol 11, No 2 (2020)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jrm.2020.011.02.12

Abstract

In this paper, the effect of welding parameters on the shear strength of Al-PVC hybrid structures was discussed. This Research developed welding parameters in the form of Plunge Depth, heating time, and clamping frame materials. By these different parameters would result in different shear strength of welded materials. Following optimization of the process, a detailed comparison of the properties and microstructures of two different materials (meranti wood and ASTM A36 Steel) would affect to different values of thermal conductivity. The Aluminum used was Al 1100, which was welded by using a friction stir spot welding method with Polyvinyl Chloride (PVC). In this study, by the different heating times, the shear test was carried out with the ASTM D3163 standard. In this study, it was found that the maximum temperature of Aluminum occurs during the 2nd second of the welding process and then decreased in the 5th second until 60th second. However, the optimum shear strength found at 20th second. Following heat transfer and degradation materials, the 2mm plunge depth has a higher temperature and higher shear strength than 1,5mm plunge depth. Differences in the response of the two depth were attributed to the difference in mechanical interlocking. This study found that the ASTM A36 clamping frame maximum shear load of 182.4 N is higher than meranti wood frame of 125.5 N. Differences in these value are attributed to the differences of the thermal conductivity, which meranti wood had a lower thermal conductivity than ASTM A36. These have findings significant implications for the commercial application of welding hybrid structures. The best way to take advantage of the benefit of AL-PVC Structure Hybrid for friction stir spot welding would appear to be 20 second heating time, 2mm plunge depth with ASTM clamping frame.
Pengaruh Kadar Karbondioksida (CO2) dan Nitrogen (N2) Pada Karakteristik Pembakaran Gas Metana Wahyudi, Djoko; Wardana, ING; Hamidi, Nurkholis
Rekayasa Mesin Vol 3, No 1 (2012)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (221.112 KB)

Abstract

One of the renewable energy is biogas. Biogas has a great chance in its development. Biogas resulted from fermentation process is consists of: CH4 (55-75%), CO2 (25-45%), H2 (1- 5%), N2 (0-0.3%), O2 (0.1-0.5%), and H2S (0-3%). If biogas is cleared from polluter well it will have the same characteristics with natural gas. Components of the polluter water (H2O), hydrogen and as sulfide (H2S), carbon dioxide (CO2) and some particulates should be eliminated to achieve pipeline quality gas. In order to understand how the influence of the levels of CO2 and N2 of the methane combustion characteristic. The observation was conducted experimentally by burning a mixture of stoichiometry (methane gas and air) with a percentage of CO2 and N2 in the transparent fuel square-shaped space with dimensions 500 x 200 x 10 mm. The results showed that the levels of CO2 and N2 affect the combustion process, it causing the blue flame to be fade.It indicated the combustion is not perfect and the levels of CO2 and N2 inhibits the collision reaction between molecules of methane gas and air molecules. The result also showed that CO2 reduce the flame speed. Keywords: energy, CO2, N2, combustion characteristic, methane gas, air
Karakteristik Produksi Browns Gas Dengan Menggunakan Tenaga Matahari Widhiyanuriyawan, Denny; Hamidi, Nurkholis; Wijono, Wijono
Jurnal Rekayasa Mesin Vol 4, No 1 (2013)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (211.847 KB)

Abstract

Renewable energy has potentials to be developed to meet our energy needs in the future. One promising energy source is browns gas. Browns gas is a mixture of di-atomic and mono-atomic of hydrogen and oxygen. One effort to produce browns gas is through the process of electrolysis of water. However, the process of electrolysis still considered a process uneconomical and inefficient, since the energy of electrochemical decomposition of water is relatively high. Thus, the challenge of brown gas production is reducing electrical energy. In this study, we propose to use solar energy for browns gas production plant, since the solar energy is environmentally friendly energy sources available so abundant in Indonesia. The experiment was carried out in two methods. First, the electrolysis was done using electricity produced by the solar panel directly without voltage control. The second method, the voltage of electricity from the solar panel was controlled using a regulator then it used for the water electrolysis. The results show that the direct method generates fluctuative electricity with the rate power of 29.67 Watt. This electricity was used for electrolysis process and produced brown gas 0,1393 g for 4 hours. On the other hand the in-direct method generated power relatively constant at 18.3 Watt and produced the brown gas about 0.1365 g.Keywords: solar energy, browns gas, electrolysis, hydrogen
Pola Aliran Dua Fase Gas - Fluida Non Newtonian Melalui Belokan Pipa Kusumaningsih, Haslinda; Hamidi, Nurkholis; Sabila, Adriazka Fasa
Rekayasa Mesin Vol 10, No 3 (2019)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jrm.2019.010.03.12

Abstract

Two-phase flow applications can be used in chemical reactors, fuel cell and a cooler of electronic devices. Nowadays, the study on multiphase flow is concern with the gas-non Newtonian liquids flow. Since, non-Newtonian liquids commonly used in both industrial and medical applications such as blood flow, polymer and chemical solutions. The viscosity of a non-Newtonian liquid cannot be described by Newton?s law viscosity. The viscosity will affect flow behavior in pipes depends on the rheology of the fluid. The purpose of this study is to further investigate the flow pattern characteristic of gas-Newtonian/non-Newtonian liquid two-phase flows in a normal channel. Ultrapure water, polyacrylamide aqueous solutions (PAM) were used as test fluids, while argon gas as the test gas. Liquid and gas were introduced in T-junction, which placed on the upstream of the test section. In this study, the polyacrylamide concentration was variated on 0.1% wt and 0.4% wt. Moreover, the flow rate of liquids tested were variated on 0.1167 m3/s, 0.183 m3/s, 0.25 m3/s; and 0.283 m3/s. Therefore, the gas tested was variated on 0.083 m3/s, 0.167 m3/s, and 0.25 m3/s. The circular channel and bend pipe were used in this study, which has hydraulic diameter of 25.4 mm. The high-speed video camera was used to record the flow patterns in the bend as the test section. The flow pattern, bubble length, bubble velocity and void fraction were determined by analyzing the video image of the flows. Slug and plug flow patterns mostly appear in this study for each variation of liquids tested. Increasing gas superficial velocity induced the longer bubble. Furthermore, because of the higher viscosity of the non-Newtonian liquid,  the bubble nose of gas-non Newtonian liquid two-phase flow becomes sharper than the bubble nose of gas-Newtonian liquid two-phase flow. 
Analisa Perpindahan Panas dan Pressure Drop Fluida Nano Al2O3-Air Proses Pendinginan dengan Metode Simulasi Marali, Aryati Muhaymin; Wahyudi, Slamet; Hamidi, Nurkholis
Jurnal Rekayasa Mesin Vol 9, No 2 (2018)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (410.644 KB) | DOI: 10.21776/ub.jrm.2018.009.02.6

Abstract

Conventional heat transfer system is unable to absorb heat well. Various methods have been done to enhance heat transfer. One of them is the method by using nanofluid which has been done by many researchers; due to the better thermal performances compared to base fluid. The research aims to observe the enhancement of convective heat transfer and pressure drop in the cooling process by using Al2O3 – Water nanofluid. The volume concentration of the Al2O3 varied from 0.2% and 0.3% with 30 nm diameter nanoparticles flowing in a double pipe with the opposite direction. The result showed that the increase of the particle volume concentration leads to enhance convective heat transfer coefficient and pressure drop. The two variables of measurement showed the average heat transfer coefficient increased about 21% with 0.2% and 0.3% volume concentration compared to base fluid. Pressure drop increased about 22.86% with 0.2% and 0.3% volume concentration. In conclusion, the performance of nanofluid slightly increased together with the increase of volume nanofluid concentration.