Karakteristik temperatur fluida dingin pada grooved double pipe heat exchanger

Heat exchangers have widespread applications in many industrials process. There are many kind of heat exchanger. One of the simply heat exchanger is double pipe heat exchanger. The need for lightweight and enhancing the heat transfer of heat exchanger accomodated by surface engineering. One of the surface passive technique applications is groove. Incising groove in pipe as concerned wide consideration as it need no additional power, decrease in weight of system and hence give more benefit in heat transfer. The characteristics of heat transfer in grooved double pipe heat exchanger was investigated experimentally in this article. The aim of this investigation is to reveal the phenomenon of temperature characteristics of cold fluid in the heat transfer process in the grooved double pipe heat exchanger. In this study, water are used as both hot and cold fluid with counter flow pattern, and the water flow rate equal to 15 lpm for both fluid. Grooves were incised on the annulus area in the outer wall of tube side with rectangular shape and circumferential pattern. The characteristics of groove dimension that are height of groove is 0,3 mm; distance between grooves is 8 mm; and the groove space which is as independent variables are 1 mm and 2 mm. The data from 1 mm and 2 mm grooves space were compared with no grooved double pipe heat exchanger data (smooth pipe). The hot fluid temperature is 50 ± 0,50C while the cold fluid temperature is 30 ± 0,50C. The temperature data on the inlet and outlet side of heat exchangers for smooth pipe, 1 mm and 2 mm groove space were compared to find out the characteristics of increasing cold fluid temperature. This study used the temperature rate and temperature acceleration method to compare the variables. The result shows that groove installation increases the amount of heat absorbed by cold fluid. The heat exchanger with 1 mm groove spaces, was able to absorb heat about ± 2.3 % better than heat exchanger with 2 mm groove space and 13,1 % better than heat exchanger with no groove

PERAN PENGELOMPOKAN MOLEKUL PADA HYDROUS ETANOL TERHADAP KINERJA MESIN

In this study observed the role of molecular clustering on engine performance produced by hydrous ethanol fuel (95.5% v). The test was performed using variation load for four-cylinder motor. Engine performance is measured using Brake Power Engine load cell type indicator TD 800PM. The engine performance produced by anhydrous ethanol was also tested. The resulting engine performance of both fuels is compared. The results showed that the power produced by hydrous ethanol was slightly higher than that of anhydrous ethanol. The charging effisiency generated by hydrous ethanol is upper than that of anhydrous ethanol.Pada penelitian ini diamati peran pengelompokan molekul terhadap kinerja mesin yang dihasilkan bahan bakar hydrous etanol (95,5%v). Pengujian dilakukan menggunakan pembebanan bervariasi pada motor bakar satu silinder empat langkah. Kinerja mesin diukur menggunakan Engine Brake Power indikator load cell tipe TD 800PM. Kinerja mesin yang dihasilkan oleh anhydrous etanol juga diuji. Kinerja mesin yang dihasilkan kedua bahan bakar tersebut dibandingkan. Hasil penelitian menunjukkan Daya mesin yang dihasilkan hydrous etanol sedikit lebih tinggi dari anhydrous etanol. effisiensi pengisian yang dihasilkan oleh hydrous etanol lebih tinggi dari anhydrous etanol

The design of a test rig for the identification of dynamic coefficients of a high temperature magnetic bearing

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 70-71).This thesis is a report on the research and Micrographics. development to design a test rig for the identification of the dynamic coefficients of a radial magnetic bearing. The test rig development is intended for dynamic coefficient observation for a range of operating conditions that are a function of rotor speed and temperature. A linear model was used in this study. The coefficients observed are the proportionality constants of the magnetic bearing force to the relative positions, currents, and their derivatives. The identification is done by means of frequency excitation. Regression analysis is performed to extract the coefficients from the Fourier Transform of the experimental data. This specific study employs a homopolar magnetic bearing with electromagnetic bias coil. The test rig development requires vibration and thermal analyses. The thesis describes the analysis procedures and their effects on the final design. Two approaches were employed for vibration analysis, the transfer matrix method and the finite element method. The transfer matrix method is used to predict the critical speed of the rotor. The finite element method is used to predict the frequency response of the designed rig. Thermal analysis is used to predict the energy required to achieve the desired temperature on purpose. The finite element model is used to predict the thermal expansion of the rotor and bearing. Finally, the experimental setup is designed using a computer data acquisition system to obtain an integrated testing system

A design of a cocoa bean sorting machine

Cocoa plantations have employed thousands of farmer families throughout Indonesia, as well as have been the third largest export among the plantation sub-sector after rubber and oil palm. Therefore, the potential for the development of the cocoa industry as one of the drivers of growth and income distribution is very open. Cocoa bean production in Indonesia continues to increase, but the quality produced is still diverse such as less fermented, not dry enough, uniform bean size, high skin content, high acidity, and very diverse flavors. In this research, efforts to overcome these problems are accomplished by designing a cocoa bean sorting machine that can separate clean cocoa beans and root debris from cocoa beans so as it is expected to make it easier for cocoa farmers, workers, entrepreneurs and industries to more easily get a cocoa bean sorting machine so that the quality of cocoa beans improves and their selling price increases. Seeing these challenges, the authors took the initiative to create a new design a cocoa bean sorting machine with a simpler and more precise design