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This paper presents experimental investigations conducted to understand the influence of water-soluble drag-reducing polymers (DRPs) in single- and two-phase (stratified wavy) flow on flow-field characteristics. These experiments have been presented for water and air–water flowing in a horizontal polyvinyl chloride 22.5-mm ID, 8.33-m long pipe. The effects of liquid flow rates and DRP concentrations on streamlines and the instantaneous velocity were investigated by using particle image velocimetry (PIV) technique. A comparison of the PIV results was performed by comparing them with the computational results obtained by fluent software. One of the comparisons has been done between the PIV results, where a turbulent flow with DRP was examined, and the laminar–computational fluid dynamic (CFD) prediction. An agreement was found in the region near the pipe wall in some cases. The results showed the powerfulness of using the PIV techniques in understanding the mechanism of DRP in single- and two-phase flow especially at the regions near the pipe wall and near the phases interface. The results of this study indicate that an increase in DRP concentrations results in an increase in drag reduction up to 45% in single-phase water flow and up to 42% in air–water stratified flow.

Multiphase flow industrial applications require reduced frictional pressure drop (drag) and lower operating costs. Drag reducing polymers (DRPs), which do not require additional infrastructure, meet this requirement. Therefore, this study investigated the effects of water‐soluble polar ZETAG® 8165 and nonpolar oil‐soluble polyisobutylene (PIB) DRPs on pressure gradient and percentage drag reduction using two‐phase air‐water and air‐oil flows, and three‐phase air‐oil‐water flow. The conduit comprised a 22.5 mm I.D. and 2.48 m long horizontal pipe. The fluid flow pattern and DRP shear stability were also studied. The functional mechanism of DRP, not adequately addressed in the literature, was especially revisited. This work suggests that the resultant interaction between the DRP state and the external environment dictates its ability for dampening turbulent eddies, streamlining the velocity field, and eventually increasing the thickness of the laminar sublayer. The DRP state includes its chemical structure and hydrodynamic size. On the other hand, the external environment comprises fluid flow pattern, polarity, phase morphology, and intensity of turbulence. Hence, the functional mode of a DRP is more involved than what the literature usually reports. ZETAG® 8165, having longer branches and ion‐pairs around the backbone, showed less shear degradation than the fairly straight‐chain PIB. The effects of these structural differences were also well‐reflected in their varying abilities to transpose flow pattern, and reduce drag and pressure gradient. For a given DRP, the air flow rate promoted or demoted the DRP performance, depending on the experimental design.

Improving the vibration isolation for the seat of small vehicles under low excitation frequencies is important for providing good comfort for the driver and passengers. Thus, in this study, a compact, low-dynamic, and high-static stiffness vibration isolation system has been designed. A theoretical analysis of the proposed quasi-zero stiffness (QZS) isolator system for vehicle seats is presented. The isolator consists of two oblique springs and a vertical spring to support the load and to achieve quasi-zero stiffness at the equilibrium position. To support any additional load above the supported weight, a sleeve air spring is used. Furthermore, the two oblique springs are equipped with a horizontal adjustment mechanism that is aimed to reach higher frequencies with the existed stroke when a heavy load is applied. The proposed system can be fitted for small vehicles, especially for B-segment and C-segment cars. Finally, the simulation results reveal that the proposed system has a large isolation frequency range compared to that of the linear isolator.

Frictional pressure drop has been grasping the attention of many industrial applications associated with multi-phase and academia. Alongside the United Nations, the 2030 Agenda for Sustainable Development calls for the exigency of giving attention to economic growth, a considerable reduction in power consumption is necessary to co-up with this vision and to adhere to energy-efficient practices. Thereinto, drag-reducing polymers (DRPs), which do not require additional infrastructure, are a much better option for increasing energy efficiency in a series of critical industrial applications. Therefore, this study evaluates the effects of two DRPs—polar water-soluble polyacrylamide (DRP-WS) and nonpolar oil-soluble polyisobutylene (DRP-OS)—on energy efficiency for single-phase water and oil flows, two-phase air–water and air-oil flows, and three-phase air–oil–water flow. The experiments were conducted using two different pipelines; horizontal polyvinyl chloride with an inner diameter of 22.5 mm and horizontal stainless steel with a 10.16 mm internal diameter. The energy-efficiency metrics are performed by investigating the head loss, percentage saving in energy consumption (both per unit pipe length), and throughput improvement percentage (%TI). The larger pipe diameter was used in experiments for both DRPs, and it was discovered that despite the type of flow or variations in liquid and air flow rates, there was a reduction in head loss, an increase in energy savings, and an increase in the throughput improvement percentage. In particular, DRP-WS is found to be more promising as an energy saver and the consequent savings in the infrastructure cost. Hence, equivalent experiments of DRP-WS in two-phase air–water flow using a smaller pipe diameter show that the head loss drastically increases. However, the percentage saving in power consumption and throughput improvement percentage is significantly compared with that found in the larger pipe. Thus, this study found that DRPs can improve energy efficiency in various industrial applications, with DRP-WS being particularly promising as an energy saver. However, the effectiveness of these polymers may vary depending on the flow type and pipe diameter.