Reports on multi-flight screw metering of free flowing solid particles, with side entry feed, could not be found in the available literature. But since the author worked to investigate its applicability as a seed metering mechanism for grain drills, the present work was considered essential as the first step. For this purpose, samples of 15 different free flowing particulate materials were closely sized and a test rig designed and constructed. Nine rotors of three, four, and five slots or flights were considered at speeds of 20, 40, 60, 80, and 100 r/min as desired. All experimental runs were replicated three times and the average values of the volumetric flowrates for each material, speed, and rotor were found. At the end a total of 410 data points were considered for analysis of the data based on dimensional analysis. The variable dimensionless groups were selected and analysed in such an order to produce linear relations. The overall results can be represented by the following equation: It was concluded that metering, as described by the above equation, was predictable within the limits considered for each dimensional group studied.
The aim of this study is to evaluate the thermal hydraulic parameters such as, Minimum DNBR, fuel, clad and coolant temperatures of the Tehran Research Reactor (TRR) core in order to assure that the thermal limitations are not exceeded at full power and steady-state and the loss-of-flow accident (LOFA) operating conditions and the existing design is adequate to assure that the consequences from this anticipated occurrence does not lead to a severe accident. The PARET and TRANS computer codes were used to analysis thermal-hydraulic and safety parameters under study steady-state conditions. Furthermore the LOFA as a consequence of two type of transients are analyzed; one related to main cooling pump failure accident (slow LOFA), and the other related to accidentally opening the flapper valve whereas the main cooling pump is in working (fast LOFA). The steady-state analysis involves the determination of the departure from nucleate boiling ratio (DNBR), the temperatures profile, heat flux across the hottest channel and etc. The LOFA analysis involves the power and coolant flow rate, the fuel centerline, clad surface and coolant outlet temperatures, and the occurring of coolant flow reversal.
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