1. Introduction
The behavior of boundary layers across a stretched surface is essential because it happens in many engineering systems, such as extrusion-produced materials, paper and glass-fiber production. Polymer is constantly extruded to a windup roller from a die in industry, where it is used to make a variety of sheets and filaments. In these circumstances, the rate of cooling in the process and the stretching process determine the final product’s admirable characteristics. Researchers are currently interested in nanofluids flow across an expanding sheet.
Sakiadis [
1] presented the concept of boundary layer flow over a moving solid sheet for the first time. Crane [
2] is widely acknowledged as a pioneer in boundary layer flow dynamics on stretched surfaces. When a flat sheet travels linearly in its plane due to homogeneous stress, the boundary layer flow of a Newtonian fluid becomes incompressible. Gao et al. [
3] investigated the analytical treatment of unsteady fluid flow between two infinite parallel surfaces of nonhomogeneous nanofluids with the help of the collocation method. Cui et al. [
4] studied the influence of convection analysis of nanofluid flow over the stretched sheet with heat production and chemical reaction. Second-grade nanofluid flow through the porous sheet with activation energy, binary chemical reaction, and Marangoni limitations effects were studied by Gowda et al. [
5].
The importance of heat transfer in engineering and industry has piqued the interest of researchers. In various systems, including electron devices and heat exchangers, convectional fluids such as water and ethylene glycol may be used to convey heat. However, these base liquids have low or restricted thermal conductivities. Engineers, mathematicians, and researchers from other professions are attempting to increase the thermal conductivity of the above-stated liquids by adding a single type of nanosized particle into a mixture known as ’nanofluid’, which was introduced by Choi and Eastman [
6]. The ability of solid nanoparticles to boost the rate of heat transfer and thermal conductivity in convectional base fluids has been demonstrated in prior studies. As a result, many analysts and thermal experts have conducted numerical and experimental research to improve the heat transfer rate of nanofluid from various directions. For example, Tiwari and Das [
7] investigated single-phase models of nanofluids. As a result, many scientists, engineers, and mathematicians have given this model strong consideration [
8,
9,
10,
11,
12,
13,
14]. Additionally, researchers developed a novel kind of nanofluid that incorporates two different types of solid particles into a single convectional base fluid to overcome the need for better heat transfer rates in the industry and other areas. It is worth noting that in hybrid nanofluid [
15], the thermal conductivity of the ordinary base fluid is higher than in basic nanofluid.
In physics, chemistry, and engineering, the study of magnetic field effects is crucial. Several metalworking procedures use the drawing of continuous filaments or strips through a quiescent fluid to cool and stretch metal strips. The techniques referred to are drawing, annealing, and thinning copper wire. Consequently, the quality of the final product is highly reliant on the rate at which these strips are dragged through an electrically conducting fluid subjected to a magnetic field and the desired feature in each of these conditions. Ali et al. [
16] and Hamad [
17] investigated the flow of water-based nanofluids across a stretched sheet affected by a magnetic field. Ali et al. [
18] examined free convection MHD flow of viscous fluid in a vertical circular tube using damped shear and heat flux. Awan et al. [
19] examined the MHD oblique stagnation point flow of second-grade fluid across an oscillating expanding sheet.
Radiation heat transfer flow is crucial for the efficient design of nuclear power plants, gas turbines, and other propulsion engines used in airplanes, missiles, satellites, and spacecraft. Consequently, Wang et al. [
20] examined thermal radiation for Darcy-Forchheimer nanofluid flow using entropy. Ali et al. [
21] examined the melting influence on Cattaneo-Christov and thermal radiation characteristics for aligned MHD nanofluid flows, including microorganisms across the leading edge through the FEM technique. Xiong et al. [
22] investigated 2D Darcy-Forchheimer flow for hybrid nanofluids with heat sink-source and unbalanced thermal radiation effects. According to Hasona et al. [
23], radiotherapy for cancer thermotherapy mainly depends on thermal radiation.
Bioconvection is a natural phenomenon that results from microorganisms’ random movement in single-cell or colony-like forms. Numerous bioconvection systems are based on the movement of microorganisms in two specific directions. For instance, when there is no movement, gyrotactic bacteria can travel in the opposite direction of gravity. Microorganisms move in a direction determined by bioconvection’s asymmetric mass distribution balance. Bioconvection is required for various bio-micro systems, including biotechnology and enzyme biosensors. A floating algae solution was introduced to demonstrate the bioconvection mechanism [
24]. Plesset and Winet [
25] developed the first theoretical model of bioconvection that included a diverse variety of mobile microorganisms. As a consequence of this study, Kuznetsov [
26] developed a computer model to illustrate how cell deposition facilitates bioconvection growth. Waqas et al. [
27] studied microorganisms in an electrically conductive viscous nanofluid on a porous stretched disc. Khan and Shehzad [
28] investigated the Carreau nanofluid bioconvection flow across an expanding surface. Balla et al. [
29] explored the bioconvection of oxytactic bacteria in a porous square enclosure using thermal radiation. Bioconvection is used in various fields, including pharmaceuticals, biological polymer synthesis, ecologically friendly applications, sustainable fuel cell technologies, microbial improved oil recovery, biosensors and biotechnology, and mathematical modeling enhancements.
We observed no study on bio-convective Prandtl hybrid nanofluid flow in the literature. The aim of the current article is to boost the heat transfer rate. The novelties of our research are: (i) Prandtl non-Newtonian fluid is considered, (ii) how effect inclined MHD, Brownian motion and thermophoresis diffusion, and motile microorganism on fluid flow, (iii) convective boundary effect is also considered, and (iv) nanofluid and hybrid nanofluid flow results are compared.
In this investigation, the following scientific research questions are answered:
What is the impact of multi-buoyancy forces, inclined magnetic field, and Prandtl parameters on the fluid velocity subject to mono and hybrid nanofluids flow?
What is the effect of the magnetic field, Prandtl parameters, Brownian motion, and thermophoresis on the temperature and heat transfer rate for mono and hybrid nanofluid flow?
How is the concentration affected by the magnetic field, Lewis number, chemical reaction parameter, Brownian motion, and thermophoresis for mono and hybrid nanofluid flow?
Determine how bio-convection influences motile dispersion and mass transfer of motile microbe density?
2. Mathematical Formulation
Considered Prandtl hybrid nanofluid with two-dimensional incompressible steady flow due to an expanding sheet with motile microorganisms. The coordinate system
is chosen that is perpendicular and flow is assumed at
. An inclined magnetic field is applied to the fluid flow, which makes an angle
with the
x-axis and
(
a is constant) is the velocity with which the plate is expanded along the
x-axis as shown in
Figure 1.
The governing equations of Prandtl hybrid nanofluid are given as ([
30,
31]):
All the involved terms in these equations are defined in nomenclature. The following are the suitable boundary limits [
32]:
By utilizing the similarity relations given below, the above PDEs can be transformed into ODEs [
33]
where
By the above similarity relations Equation (
1) is justified identically and Equations (2)–(5) are rewritten as:
and Equations (6) and (7) become
where
,
f ,
, and
are functions of
. Moreover, prime stands for differentiation,
denotes the magnetic parameter,
is Prandtl fluid parameter,
denotes elastic parameter, the buoyancy ratio parameter is expressed as
,
is the parameter of thermophoresis,
is thermal Biot number,
shows the Brownian motion parameter,
indicates mixed convection parameter,
signifies the Lewis number,
indicates Rayleigh number of bioconvection,
is a chemical reaction parameter,
denotes bioconvection Lewis number,
indicates bioconvection constant,
shows the Prandtl number, and
be Peclet number.
The following are the definitions for the physical quantities [
32]:
At the surface is shear stress and is heat flux.
Utilizing the predefined similarity relations, expressions (19) become
here,
pertains Reynolds number.
4. Results and Discussion
Numerical results of physical parameters for two cases of fluid flow are determined as follows: a =
/Water (simple nanofluid) and b =
/Water (hybrid nanofluid). The above results are verified when compared with previous
results in limiting cases, as shown in
Table 4. Each physical parameter such as velocity, temperature, concentration, and microorganism are evaluated numerically by giving predetermined values to all of the other factors involved. All figs. presented results of two type flows such as single nanofluid (
/Water) flow and hybrid nanofluid (
/Water) flow.
Figure 2 and
Figure 3 illustrate the impact of Prandtl fluid parameter (
) and elastic parameter (
) on velocity profile. The velocity profile of simple nanofluid and hybrid nanofluid increase by increasing the value of (
) and (
). This occurs because boosting the Prandtl fluid parameter reduces fluid viscosity. As a result of higher Prandtl fluid values, fluid becomes less viscous, and velocity profiles increase.
Figure 4,
Figure 5,
Figure 6,
Figure 7 and
Figure 8 show the effects of
and
on the velocity of simple nanofluid and hybrid nanofluid flow. The velocity profiles for simple and hybrid nanofluid flow decline by boosting the values of all parameters. By boosting
M, the Lorentz forces slowdown the fluid motion.
The impacts of (
) and (
) on temperature is illustrated in
Figure 9 and
Figure 10. It has been observed that by growing the values of both parameters, temperature curves of nanofluid and hybrid nanofluid declined. Moreover, temperature curves are enhanced while boosting the values of
and
as shown in
Figure 11,
Figure 12,
Figure 13 and
Figure 14. This type of behaviour is explained by the fact that enhancing the Brownian motion parameter causes an increase in the random motion of fluid particles. This increase in random motion raises the mean kinetic energy of fluid particles, which raises the temperature of the simple nanofluid and hybrid nanofluid. Physical, thermal Biot number proves that an increase in the energy gradient toward the surface results in a reduction in the thickness of the thermal boundary layer.
Figure 15 and
Figure 16 display the impacts of magnetic parameter and Lewis number on concentration profiles of
/Water and
/Water. From these figures it has been visualized that concentration of both fluids enhanced with the increment in
M while opposite behavior is observed for higher values of
.
Figure 17,
Figure 18 and
Figure 19 demonstrate the concentration of simple nanofluid and hybrid nanofluid flow for parameters
, and
, respectively.
Figure 17 shows increasing behavior of
/Water and
/Water concentration profiles for boosting values of
whereas decreasing behavior has been observed for growing values of
and
as shown in
Figure 18 and
Figure 19. In reality, when
increases, the fluid particles accelerate rapidly, resulting in an increase in kinetic energy that causes the boundary layer to grow. Physically, the random acceleration decreases as the quantity of
grows, the flow of fluid particles from peak areas to bottom regions improves fast.
Figure 20,
Figure 21,
Figure 22 and
Figure 23 portray behavior of motile microbe profiles (
) by varying parameters for both fluids. The impacts of the bio-convected Peclet number (
) and the magnetic parameter (
M) has been illustrated in
Figure 20 and
Figure 21. It is observed that the microorganisms boosts along with
M, but it declines with the increase in
.
Figure 22 and
Figure 23 depict the profiles of microbes for
and
. It is noted that the profiles of microbes decrease for the boosted values of
and
.
Table 5 signifies the numerical values of Nusselt number and local skin friction coefficient versus different values of parameters.