ANALISIS PENGARUH KECEPATAN ALIRAN FLUIDA DINGIN TERHADAP EFEKTIVITAS SHELL AND TUBE HEAT EXCHANGER

Abstract

As a heat exchanger where high fluid temperatures flow to lower fluid temperatures, a heat exchanger is expected to have great effectiveness. Theoretically the increase in flow velocity will increase the value of effectiveness and can enlarge the Reynold numbers and Nusselt numbers which then increase the heat transfer by covection. This test is performed by forced convection by varying the speed of the cold fluid (Vc) which is 1.19 m / s to 2.91 m / s with a constant hot fluid velocity (Vh) = 1.98 m / s at the temperature of the incoming hot fluid ( Th, 1) = 60ºC and cold fluid temperature (Tc, 1) = 32ºC which is made constant. From the results of the study obtained the characteristics of a heat exchanger increases with the increase in the speed of cold fluid. Characteristics of heat exchangers include Reynold numbers (Re), Nusselt numbers (Nu), convection coefficients (h), overall convection coefficients (U), heat transfer (q), and effectiveness (ε). Where is obtained the most optimal characteristics at cold fluid velocity (Vc) = 2.91 m / s and minimum cold fluid velocity (Vc) = 1.19 m / s, it is found that increasing the speed of cold fluid flow can increase the performance or effectiveness of a device heat exchanger. but this increase in effectiveness does not go on where it will reach a point where the effectiveness does not increase but decreases. Where the cold fluid velocity (Vc) = 1.19 m / s can absorb heat until the temperature of the cold fluid rises to 44.7ºC and until the speed (Vc) = 2.91 m / s the increase in temperature of cold fluid is only up to 41.6ºC because the shorter contact time makes the heat absorption of the hot fluid shorter, then if the speed of the cold fluid is increased continuously it will make the absorption of heat from the hot fluid go down which results results in the effectiveness of the heat exchanger going down.