Influence of process variables on residence time distribution and flow patterns of tarhana in a twin-screw extruder

Ainsworth, Paul; İbanoğlu, Şenol; Hayes, George D.

doi:10.1016/s0260-8774(97)00001-0

Cited by 24 publications

(20 citation statements)

References 11 publications

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“…Table 1 shows the increase in degree of fullness from 0.04 to 0.56 with an increase in the solids flow rate from 15.2 to 206 kg=h, while the degree of fullness decreases from 0.3 to 0.1 with an increase in the screw speed from 10.8 to 28 rpm ( Table 2). Ainsworth et al [9] and Yeh and Jaw [10] have reported that an increase in the screw speed and=or decrease in the solids flow rate leads to a decrease in the degree of fullness, which also supports the above findings. It is well understood that the material in the screw extruder or conveyor with a low degree of fullness is subjected to less compaction compared with the case of high degree of fullness.…”

Section: Degree Of Fullnesssupporting

confidence: 65%

“…Thus, from the foregoing discussion, it can be said that the increase in the degree of fullness increases the Pe and the corresponding N. Also, the lower degree of fullness results into less compaction of the solids and hence more mixing as compared to the case of higher degree of fullness. [9,10] The values of N and Pe decrease from 64 to 25 and 127 to 48.1, respectively, with an increase in the screw speed from 10.8 to 28 rpm for a given solids flow rate (Table 6). This trend indicates the inter-mixing at higher screw speed and the flow approaches mixed flow pattern.…”

Section: Flow Behaviormentioning

confidence: 99%

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Hydrodynamic Characteristics of a Pilot-Scale Screw Conveyor Dryer

2007

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This article presents results of an experimental study on the flow characteristics of a pilot-size screw conveyor dryer (SCD). In particular, the effects of granular solids flow rate (15.2-206 kg/h) and screw speed (10.8-28 rpm) on the residence time distribution (RTD) were studied using sand as the model material. The RTD was measured using a dynamic step change in the solids flow rate. Parameters such as solids holdup, degree of fullness, mean residence time, and uniformity of the discharge flow were studied. The solids holdup and hence the degree of fullness was found to decrease with increase in the screw speed and decrease with the solids flow rate. The mean residence time was found to decrease with an increase in the screw speed, as expected. The screw speed and the solids flow rate strongly affected the discharge uniformity. An optimum value of the degree of fullness was observed with regard to the solids flow rate. Over the operating range examined, the solids flow pattern was close to plug flow, as indicated by high values of N and Pe number.

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Section: Degree Of Fullnesssupporting

confidence: 65%

Section: Flow Behaviormentioning

confidence: 99%

Hydrodynamic Characteristics of a Pilot-Scale Screw Conveyor Dryer

2007

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“…Altomare and Ghossi (1986) showed that screw speed did not significantly affect the shape of the RTD and an overall mixing pattern in a twin-screw extruder. Ainsworth, Ibanoglu, and Hayes (1997) and Yeh, Hwang, and Guo (1992) reported that flow approaches to mixed flow due to decrease in the degree of fill of an extruder and compactness of material in the extruder as screw speed increase at constant feed rate, and stated that the degree of fill of an extruder increase with the increase in feed rate. In this study, the flow rate was not kept constant, increasing the screw speed increased the flow rate, and the flow pattern did not approach to mixed flow with increase in the screw speed.…”

Section: The Effect Of Screw Speedmentioning

confidence: 99%