## 1 Introduction
[41] examined several types of nanoparticles in a computational study of heat exchanger microchannels. For all types of nanofluids, they found an improvement in thermal performance and pressure drop. It is believed that building a heat transmission device only based on the first law of thermodynamics would be inefficient, and that the second law of thermodynamics must also be taken into account when developing heat transfer devices. The second law of thermodynamics states that the design of a system must be such that it entails the lowest possible rate of entropy production. A review of the literature indicates that the analysis of forced heat transfer through channels using the second law has rarely been performed. [PERSON] and [PERSON] [42] carried out an analysis in a tapered irregular channel to evaluate the entropy production of magnetomicropolar fluid with thermal radiation. Entropy production decreased when the magnetic parameter and thermal radiation parameters increased. The effect of geometrical factors on entropy production in cross-wavy channels was explored by [PERSON] et al. [43]. Their findings indicate that heat transport is a primary cause of entropy production in the geometry under consideration. [PERSON] et al. [44] investigated entropy production in a vertical tube with mixed convection Poiseuille flow of molybdenum disulfide Jeffrey NF. The results indicated that when the temperature decreases and the Brickman number increases, entropy production increases. [PERSON] et al. [45] studied the entropy generation features of NF flow in sinusoidal wavy channels numerically and discovered that the lowest entropy production rate decreases as the Richardson number increases. CuO-water NF flow over a heat source inside a conduit with abrupt extension and shrinkage was studied by [PERSON] et al. [46]. The entropy generation number increases when the NF concentration and surface temperature of the heat source increases, whereas it decreases when the blockage ratio is increased. It is pertinent to mention that the geometry of tubes (twisted and straight), flow direction (countercurrent and concurrent), and flow rates that impact the Re numbers are critical to the performance of heat exchangers [46]. It was also found that the thermophysical properties of nanofluids, such as specific heat, viscosity, thermal conductivity, and heat transfer coefficient, are of great importance for heat transfer application in heat exchangers [47]. In addition, a recent study found that flow rate in the tube side and shell side are both critical to the performance of heat exchangers [48]. Together, these studies show that the use of nanoparticles generally increases the pressure drop (up to about 17%) and increases the heat transfer rate (up to about 28%) [32; 33; 34]. While the pressure drop is actually generally increased by the presence of nanoparticles, the effects on the heat transfer rate depend, among other factors, on the flow regime. Frequently, negative effects are observed for turbulent flow, while more promising results are obtained for laminar flow. Performing two-phase simulations can report results closer to the experimental results. Of course, this behavior is not the same in all studies, and some contradictory results have been presented. To the best of our knowledge, no study has been performed to date on the modeling and simulation of the hydrothermal characteristics and entropy production of single-phase hybrid nanofluid (HNF) flow within a heat exchanger (HE) with elliptical corrugated tubes, based on a review of the literature. The current study was conducted in order to fill this research gap.