# The Design and Investigation of Hybrid a Microfluidic Micromizer
## 1 Introduction  
Today, microfluidics has become a revolutionary interdisciplinary topic with considerable interest in a wide range of bioengineering applications such as mixing, sorting, separation, detection, and reaction [1]. Microfluidic devices are the best replica of a conventional lab due to their unique abilities, such as small sample consumption, and exact control of fluid particles on the microscale [2]. In addition, microfluidics have unique properties, such as high surface area to volume ratios and rapid mass and heat transfer, which have paved the way for innovations in a variety of scientific and commercial fields, promising increased efficiency, portability, and cost-effectiveness in a wide range of applications [3]. In microfluidic devices, the manipulation of fluid particles can be challenged through microchannels with dimensions ranging from micrometres to millimetres [4]. The high degree of mixing of biofluids and biochemicals is a crucial feature in many microfluidic devices, aiming to obtain a homogeneous mixture between two different heterogeneous components under laminar flow conditions with minimum fabrication complexity [5]. Over the decades, numerous studies have been carried out, and several microfluidic micromisers have been proposed. Moreover, the extensive literature shows a wide categorisation ofmicrofluidics micromixers into two major types, active and passive micromixers, based on the external energy supply to operate [6]. Active micromixers need external sources such as electric fields, acoustic fields, magnetic fields, and photothermal effects to operate and control the mixing fluids [7]. These sources cause disturbance in the flow fluid pattern, leading to the enhancement of heterogeneous fluid species transport [8]. Such a kind of disturbance enhances the interfacial area between two different heterogeneous fluids. In addition, the main advantages of using the active actuation approach are higher mixing, which is best suitable for precise control, and a complex mixing pattern for various biofluids and chemicals [9]. Some drawbacks are also studied, as the active actuation approach needs some external source or force that consumes power and requires more space and cost compared to the passive approach and can interfere with the chemical and biological properties of fluids [10]. [PERSON] et al. [11] developed a numerical model to simulate transportation phenomena in microfluidic systems with fluorescent and ferrofluid dye that was induced by the nonuniform magnetic source. [PERSON] et al. [12] demonstrated the impact of ultrasound waves on the mixing performance of a type micromixer. They used piezoelectric transducers to generate vibrations. [PERSON] et al. [13] examined the optimisation of effective parameters and their impact on mixing quality in a 2D active-type micromixer. [PERSON] et al. [14] investigated the concentration field and flow distribution in the microchannel and observed two different circulation flows and four various rotating vortices produced in the expansion micromixer chamber by inducing AC electric fields. [PERSON] et al. [15] proposed a novel type of rhombic electro-osmotic micromixer using the principles of both convergence and divergence with microelectrodes to enhance mixing performance. They examined the performance of the micromixer by changing the angle and the combination of various rhombic elements. [PERSON] et al. [16] numerically investigated the mixing and flow characteristics of a charged heterogeneous micromixer for an electro-osmotic flow with obstacles both in the top and bottom walls. [PERSON] et al. [17] examined the electro-osmotic mixing attributes of fluid flow by a hydrophobic microchannel with interfacial slips subjected to different surface charges. They also developed a theoretical framework to solve the Poisson-Boltzmann equation. On the other hand, passive micromixers do not depend on any external energy source for fluid manipulation and actuation purposes [18].