Heat transfer in double pipe heat exchanger with circumference-rectangular grooves has been investigated experimentally. The volume flowrate of cold and hot water were varied to determine its influence on the approach temperature of the outlet terminals. In this experimental design, the grooves were incised in annular room that is placed on the outside surface of the inner pipe. The shell diameter is 38.1 mm and tube diameter 19.4 mm with 1 m length, which is made of aluminum. The flow pattern of the two fluids in the heat exchanger is a parallel flow. The working fluid is water with volume flow rate of 27.1, 23.8 and 19.8 l/minute. The temperature of water on the inlet terminals are 50±1 0 C for hot stream and 30±1 0 C for cold stream. Temperature measurements conducted on each terminal of the inlet and outlet heat exchanger. The results showed that the grooves induced the approach temperature. The change of the approach temperature from the grooves compared to that of without grooves decreased by 37.9%. This phenomenon indicates an increase in heat transfer process and performance of the heat exchanger. Groove improves the heat surface area of the inner pipe, increasing the momentum transfer and in the other hand, reducing the weight of heat exchangers itself.
An injection system is a process of burning fuel on an internal combustion engine by using an electronic system to inject fuel with air into the combustion chamber. The carburetor system uses a nozzle to blur the fuel mixture with the combustor air. The purpose of this study was to determine differences in the value of fuel consumption from the injection system with the carburetor system. This research was conducted by the experimental method. The results of the analysis showed that the average value of fuel consumption even with the injection system was 51.53ml, while the mean value of the carburetor system was 90.40 ml, this meant that the injection system was more efficient compared to the carburetor system of 44.89 ml or 47%. Conclusion injection system at any rotation is more economical than the carburetor system. It is recommended to conduct further research by taking real data that is distance and travel time.
Thermal effectiveness was performed as preliminary research in shell and coiled tube heat exchanger with addition of Al2O3 nanoparticles. In the present study, the effect of small concentration of Al2O3 nanoparticles analysis for steady state. Water is selected as the working fluid of cold fluid and refrigerant R-22 as hot fluid. The present work also includes the effect of nanoparticles on logarithmic temperature difference (LMTD), amount of heat absorbed by the water as a time series function. Based on the result, the effectiveness of water-Al2O3 nanoparticles as cold fluid shows good agreement on heat transfer parameter enhancement. The heat exchanger effectiveness increase until 2.2% compare to that of heat exchanger without Al2O3 nanoparticles. This phenomenon indicates an increases of heat transfer process inside heat exchanger. The application of water-Al2O3 nanoparticles on shell and coiled tube heat exchanger enhanced the convective heat transfer passively.
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