Description of a New Tundish Model for Treating RTD Data and Discussion of the Communication “New Insight into Combined Model and Revised Model for RTD Curves in a Multi-strand Tundish” by Lei

Analysis of Optimization Weights for Flow Field of Internal Rotation Stabilizer Coupled with Porous Retaining Wall

“…Due to the randomness of the fluid movement, different molten steel streams have different trajectories in the tundish, but the residence time distribution of the fluid in each calculation unit in the tundish still obeys the statistical law, so the RTD curve can be calculated by the function [20][21][22], and the theoretical RTD curve is shown in Figure 4. The parameters characterizing the flow characteristics of the tundish flow field can be calculated based on the RTD curve, such as the volume fraction of the mixing zone, the volume fraction of the piston zone, the volume fraction of the dead zone, the peak response time, and the short-circuit flow rate [23][24][25][26][27]. For a multi-flow reactor with a fluid domain volume of and an outlet flow rate of , the calculation formula for the theoretical average residence time of the fluid in the closed vessel is:…”

“…In order to characterize the composition deviation of molten steel flowing out of each outlet, the method of calculating the variance S is often used to investigate the consistency of the outlet stream [28]. The parameters characterizing the flow characteristics of the tundish flow field can be calculated based on the RTD curve, such as the volume fraction of the mixing zone, the volume fraction of the piston zone, the volume fraction of the dead zone, the peak response time, and the short-circuit flow rate [23][24][25][26][27]. For a multi-flow reactor with a fluid domain volume of V and an outlet flow rate of Q, the calculation formula for the theoretical average residence time of the fluid in the closed vessel is:…”

Explicit Residence Time Distribution of a Generalised Cascade of Continuous Stirred Tank Reactors for a Description of Short Recirculation Time (Bypassing)

“…The diffusion, TIS, and convection models cover a wide variety of RTD shapes. However, because of their different analytical forms, the only way to describe transitions between a bypassing condition and a non-ideal mixing condition, is to build reactor networks containing convective elements and CSTR cascades or utilising parallel CSTRs in reactor networks [13,25,28,32]. The TIS model has been generalised to a non-integer number of CSTRs in series [25], but it is also possible to utilise less than one CSTR to describe short-circuiting and bypassing effects [29].…”

“…Martin [25] generalised the TIS model to non-integer n ≥ 1 to fine-tune the resulting RTD. This generalisation has been used as a stand-alone model and as a building block in reactor networks [13,24,[26][27][28]. Toson et al [29] used the model with a narrow parameter range 0.5 < n < 1.1 to fit the RTD of a continuous powder mixer and linked n to the quality of the mixing process.…”

Characterization of single-phase flow hydrodynamics in a Berty reactor using computational fluid dynamics (CFD)

“…17 After that, Braga and Tavares (2018) also proposed a new tundish model for analyzing the residence time distributions of well-mixed tanks. 18 Their model was extended for the positive real value of n by Martin; nevertheless, this revised model was unable to appropriately distinguish between a real dead volume and a well-mixed volume. 18 It was because both flow types created a long-tail behavior in the RTD curve.…”