Fadaee, Mohammad Mahdi2026-01-302026-01-302026-01-30http://hdl.handle.net/10393/51336https://doi.org/10.20381/ruor-31724Traditional pharmaceutical and fine chemical production processes possess a high degree of flexibility because batch or semi-batch stirred tank reactors are primarily utilized, which aren't often allocated to any specific reaction or product; instead, they are flexible to produce different chemicals via various reactions at a wide range of operating conditions. This flexibility is associated with some problems, such as low heat transfer performance, poor mixing quality, and fouling. Reducing the problems associated with traditional pharmaceutical processes is included in the concept of "Process Intensification," which refers to methods and modifications implemented in a process to enhance its efficiency and economy, such as reducing equipment volume, handling chemical reactions at optimized conditions, decreasing energy consumption, and waste materials. The focus of this research was on the intensification and characterization of a coil reactor capable of handling solid-forming reactions and potentially applicable to pharmaceutical industries. This type of reactor has been partially intensified as its flow is continuous, and its volume reduced relative to batch-wise operation. In this work, oscillatory flow at different operating conditions (frequency, amplitude, and net flow rate) was applied to the fluid flowing in the reactor, aiming to better intensify its performance. First, the behavior of fluid flow inside the reactor in terms of residence time distribution (RTD) and associated axial dispersion was experimentally investigated and mathematically characterized by a statistical model. The results showed that there is a point at which the axial dispersion under oscillatory conditions is minimum. The axial dispersion was also correlated with the operating conditions and coil dimensions by a Dean number with the flow amplitude as the characteristic length. Second, the viscous power dissipation and phase shift between the coil pressure drop and velocity at different oscillatory conditions was numerically studied by a CFD model in order to better understand the relationship between the instantaneous flow field, power dissipation and the RTD variance. Third, the enhancement of the wall-to-fluid heat transfer was evaluated under non-oscillatory and oscillatory conditions. For the non-oscillatory experiments, three new correlations were developed for the thermal entrance length of coils, Nusselt number of developing laminar flow, and combined (developing and developed) flow, and the Nusselt number of turbulent flow. The result showed that the heat transfer coefficient of coils in laminar flow is not significantly dependent on the coil curvature. Then the Nusselt number of the oscillatory flow was characterized using the non-oscillatory results and correlated with the operating conditions and coil dimensions. The results showed that although oscillation can enhance the coil heat transfer coefficient, the amount of enhancement is limited by the net flow rate. Finally, the reactor performance during a sample solid-forming reaction was characterized, and the effect of oscillatory conditions on the particle size distribution was studied. The net flow rate and oscillation frequency can effectively change the particle size, while the effect of amplitude needs more investigation for different reactions. In addition, online measurement of the pressure drop for a concentrated reaction showed that oscillation can extend the operation time by decreasing the amount of fouling and consequently the risk of blocking. According to the achievements in this research, applying oscillation can provide ranges of operating conditions in which the plug flow performance, convective heat transfer coefficient, particle growth, and PSD broadness are optimized. However, these ranges are mostly independent, and for quantities related to solid forming reactions, they are case-specific. Therefore, to design a reactor for a specific solid-forming reaction, a trade-off must be established between different design parameters such that more important quantities are in acceptable ranges.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Oscillatory FlowHelical Coil ReactorsResidence Time DistributionHeat TransferSolid-forming Reaction3D Flow FieldPower DissipationPhase ShiftThesis