STUDI EKSPERIMEN PENGARUH PANJANG THROAT TERHADAP KINERJA LIQUID JET GAS PUMP (LJGP)

Liquid gas jet pump (LJGP) is a fluid machine working principle is based on the difference in momentum. The momentum generated by the gas nozzle induces in the suction chamber. Momentum transfer between the gas and the liquid jet at a place known by the throat. In the process of mixing the throat occurs between liquid and gas. This process resulted in changes in the pattern of flow and pressure rise. Changes in flow patterns before and after mixing is jet flow to Froth flow. Slowing the flow rate also resulted pressure rise. Fractions were carried with the liquid gas will be compressed in the throat after the occurrence of the mixing process. The position of the mixing process is highly dependent on the change of the liquid flow rate and gas flow rate. At high gas flow rate, the mixing process occurs away from the inlet throat and possibly occurs in the diffuser. These conditions resulted in the efficiency decreases. In order that the mixing process is always in the throat, then the necessary research that is able to find a correlation between the effect of the discharge of liquid jet and gas discharge to a long throat. A series of tests are carried out: varying the liquid flow rate on gas flow rate for length variation throat consecutive 2dt, 4dt, 6dt. The test is performed on a test section with dimensions: throat diameter (dt) = 8.5 mm, nozzle diameter = 5.7 mm or area ratio = 0.45. The test results showed that there was a long-throat effect on the performance of the entire variation LJGP to discharge liquid jet and gas discharge. LJGP overall characteristics show a similar trend for the combination of variation and discharge of liquid jet gas discharge. The trend is: the smaller gas flow rate is the lower pressure in suction chamber on liquid jet flow rate constant. While the length of the throat shows the effect of changing the length throat 4dt produce the highest efficiency compared with the length throat 2dt and 6dt for all combinations of liquid flow rate and gas flow rate