Percentage Drag Reduction Research Articles

Application of a hydrophobic coating to a pressurized pipe and its effect on energy losses and fluid flow profile

The use of additives, generally called DRAs (Drag Reducing Additives), has been proposed to re-duce the energy consumption in pressurized pipes. Although many research works have been conducted to analyze the effect of these additives, less attention have been devoted to the application of coatings to the pipe wall. This paper demonstrates that the application of a hydrophobic coating to the pipe can lead to a head loss reduction for a transition flow regime with moderate Reynolds number values (Re). For this purpose, an experiment was conducted to compare the performance of both coated and uncoated pipes by measuring the head losses and assessing the Drag Reduction Percentage (%DR) and the pipe friction factor (f). This was done for two Polyvinylchloride (PVC) pipes with different nominal diameters (PVC90 and PVC63). In addition, the flow velocity distribution was also measured in all these tests. The %DR decreased as the Re values increased, with the reduction being notably less pronounced for higher Re values. This could be explained by the fact that a partial slip condition is induced by the hydrophobic product. Its effect is significant for a transition regime where the effect of viscosity is important, but it becomes negligible for increasing levels of turbulence. No significant differences were observed in the flow distribution between coated and uncoated pipes, which seems to indicate that the velocity change could be limited to the near-wall viscous sublayer. The results of this work open an important research line aimed at reducing energy costs and the carbon footprint in pipe fluid distribution systems.

Heat transfer improvement and drag force reduction around three heated square cylinders controlled by partitions

Investigating the subject offers a pioneering approach to enhancing thermal performance and aerodynamic efficiency, unlocking novel strategies for optimizing energy utilization and air dynamics in engineering applications. In this research, a numerical study of airflow control coupled to heat transfer around several heated square cylinders is carried out at a fixed Reynolds number (Re=100). The effect of the positioning and length of the control partitions is examined. Numerical simulations are carried out using the lattice Boltzmann method with multiple relaxation times model. The obtained results reveal the existence of a critical position g=0 where a significant improvement in the Nusselt number is observed. This improvement amounts to 31.1% for the rear face of the top obstacle, 30.2% for the rear face of the central obstacle, and 36.65% for the rear face of the bottom obstacle compared to the uncontrolled case. Thus, a complete suppression of the vortex shedding is observed when the length of the partitions reaches a critical value (Lp=4D). Furthermore, a maximum percentage of drag reduction is achieved by around 6.03% for the central block and 16.67% for the two end blocks when the length of the control partitions reaches this critical value.

Experimental Study on Two-Phase (Solid-Liquid) Flows of Ground Wheat Straw in Inclined Pipes

Highlights Knife milled wheat straw-water slurry flow through inclined pipes at various inclinations is experimentally studied. Slurry concentration and pipe inclination affect the onset velocity of drag reduction and the percentage of drag reduction. The critical mass concentration of maximum drag reduction is a vital function of velocity and is independent of the pipe angle. Downhill wheat straw slurry flows exhibit the most significant reduction in drag and the smallest onset velocities. Wheat straw slurry flows moving uphill exhibit nonmonotonic variations in onset velocity and drag reduction. Abstract. Long-distance pipeline hydro-transport of lignocellulosic biomass for industrial-scale biofuel production at levels comparable to conventional oil refineries presents an economically and logistically viable alternative to fossil fuels. There is very limited understanding on the behavior of the transportation of agricultural biomass slurries in an inclined pipeline. This research is focused on a laboratory-scale investigation of 6.4 mm nominal particle length (d50 = 4.85 mm) knife-milled wheat straw-water suspensions' uphill and downhill flows for a range of pipe inclination and saturated mass concentrations. The range of pipe inclination and saturated mass concentration was -7° to +21° and 5%-30%, respectively. The inclined test section was 29 m long with a 50 mm inside diameter of a closed pipeline loop. The accuracy of the measurements was verified by calibrating the inclined pipe section with fine sand (d50 = 0.103 mm)-aqueous slurries and comparing the results with established correlations. Most wheat straw-aqueous suspensions in the inclined flows showed the characteristics of the plug flow and the transition flow regions together for saturated mass concentration, Cm = 5%-30% and the entire flow range (0.5-4.7 m s-1), with a clear dependence of both the onset velocity of drag reduction (vOD) and drag reduction (%DR) on the pipe inclination as well as the slurry concentration and the critical concentration of maximum drag reduction (Cm)cr on a specific range of suspension velocity. Because of the accelerating effect of gravity, downhill slurry flows had the lowest vOD and the highest %DR at every Cm and pipe inclination with a maximum drag reduction of 25.53% at vm = 4.5 m s-1 and Cm = 25%. Uphill flows demonstrated some nonmonotonic changes in vOD and %DR, which need more experimental data for us to reach a firm conclusion. The research outcomes could help design and operate a long-distance integrated pipeline network for biomass transportation to produce biofuels on a large scale. Keywords: Biomass transport, Drag reduction, Flow regions, Frictional pressure drop, Pipe inclination, Wheat straw slurry.

Double-decoupled inverse design of natural laminar flow nacelle under transonic conditions

The inverse design based on the pressure distribution is an essential approach to realize the improvement of Natural Laminar Flow (NLF) performance for nacelles. However, the direct definition of target pressure distribution at design point is challenging for the dilemma to consider the constraints of shock wave and laminar flow at the same time. In addition, the universality of method will be limited when the inverse design is strongly coupled with the solver. Thus, a double-decoupled methodology based on the relationship of pressure distributions between design and off-design points is proposed in this paper, which realizes the decoupling of constraints in shock wave and laminar flow on target pressure distribution as well as the decoupling of flow field solution and inverse design method. Aimed at an isolated flow-through-nacelle of high bypass ratio, the target pressure distribution with appropriate favorable gradient and shock-free feature is defined according to physical principles at the off-design point of Ma = 0.80 while the transonic and laminar performance are examined at the design point of Ma = 0.85. The solution of flow field is based on γ-Reθ transition model and the inverse design is based on residual-correction method. With the inverse design starting from off-design point, the performance of shock wave and laminar flow at design point are both improved. The local shock wave after the lip of nacelle is eliminated effectively while the streamwise length of laminar flow region is doubled and exceeds to 30% of the chord length. The percentage of drag reduction for outboard surface is 12.7% for friction drag, 7.8% for pressure drag and 10.5% for total drag. The effects of inverse design on the process of transition are analyzed with detailed flow features. The robustness of laminar flow is examined under different variation factors of freestream which are deviated from the design point.

Computational fluid dynamics and multi-objective response surface methodology optimization of perforated-finned heat sinks

BackgroundThis study analyses turbulent flow and heat transfer characteristics of a three-dimensional perforated finned heat sink using computational fluid dynamics (CFD) and response surface methodology (RSM) methods. MethodsThe effects of perforation geometry, including size (1.85 ≤ σ ≤ 2) and cross-sectional shape (square, circular, hexagonal, and triangular), as well as the Reynolds number (25, 000 ≤ Re ≤ 40, 000) as design variables, on parameters such as friction drag force, pressure drag force, total drag force, and Nusselt number were investigated. In addition, using the well-known RSM technique, three accurate models were proposed for the percentage of heat transfer enhancement (PHTE), percentage of drag reduction (PDR), and percentage of weight reduction (PWR) as the most significant design objectives for any heat sink. RSM models served as the foundation for two- and three-objective optimizations. Significant FindingsResults indicate that fins with square perforations in high σ and fins with circular perforations in low σ could achieve exceptional thermal performance (PHTE > 70%). Compared to solid fins, fins with square perforations demonstrated improved PDR performance with a 20–40% reduction in total drag force. In addition, using fins with circular perforations can reduce the heat sink's weight by 45–65% compared to solid fins. Moreover, the optimal condition for the perforated finned heat sink can be attained by considering the values 40,000 and 1,946 for Reynolds number and σ, respectively, and by selecting a circular shape for the perforations. PHTE, PDR, and PWR increase in the optimal case by 68.98%, 35.87%, and 58.86%, respectively, compared to the base case (solid fin).

The effect of polymeric drag reducing agent on pressure drop reduction in circular pipes: Experimental and statistical investigation

The present work deals with investigating the effect of adding Polyacrylonitrile (PAN) as a drag-reducing agent on the water flow’s hydraulic performance within horizontal smooth circular pipes experimentally and statistically. Several experiments were performed under various operating circumstances such as fluid flow rates at the 6,8,10 l/min for preparing turbulent flow regimes, concentrations of 25,100, 300 ppm of PAN, and inner pipe diameters of 1/2,3/4 in, and temperatures of 30, 40, and 50 °C. The maximum percentage of drag reduction (DR%) was 56 at a concentration of 300 ppm, the flow rate of 6 l/min, temperature of 30 °C and the diameter of 3/4 in. Using the Taguchi method, the results were statistically analyzed. The maximum estimated DR% value was 40.187%, and the error between the predicted and experimental values was about 10%. Moreover, the PAN concentration had a contribution of 96.5% in the polymeric solution DR. Finally, there was a new correlation to predict friction coefficient in terms of the Prandtle-Karman relation with the newly set slope as a linear function of polymer concentration. There was an excellent consistency between this correlation and the experimental data.

Aerodynamic Analysis on the Effects of Frontal Deflector on a Truck by using Ansys Software

The main causes of aerodynamic drag for automotive vehicles are the flow separation at the rear end of the vehicles. By reducing the drag force, it is possible to increase the fuel economy. Aerodynamic component i.e. Frontal Deflectors (FD) commonly used on trucks to prevent the flow separation. Frontal Deflectors themselves do create the drag, but they also reduce drags by preventing flow separation at downstream. The main aim of this paper is to quantify the effect of frontal deflectors on improving trucks aerodynamics. In this study, the simulation were ran for 6 different shapes of FD which acquires different height and different placement of FD that is mounted on the truck from the frontal roof by using ANSYS Fluent software. The design of the truck has been done in SOLIDWORK 2018 and the same design is used for analysis in ANSYS (Fluent). The two equation models used in this study are 𝑘𝑘− 𝜀𝜀 with applying the Reynolds-averaged Navier Stokes (RANS) equations for the behaviour of fluid flow around the truck. The Reynolds number used is 𝑅𝑅𝑅𝑅 = 1.1 × 106. Based on the result, all the FD’s resulted in reduction of 𝐶𝐶𝑑𝑑. The drag coefficient of all FD models differs. The velocity streamline acquired is different between the Frontal Deflector models mounted on the truck and the flow structure and vortex formation differs in various pattern formation. FD 4 produces the least value of drag. Hence, the efficiency of the truck improves. Therefore, FD 4 is the best model as the 𝐶𝐶𝑑𝑑 acquired is 0.508 with the height (15 mm) and placement of (230 mm) is the best FD to be used on a truck. Consequently, the drag reduction percentage of FD 4 compared to the truck without a FD is 32.2%.

Experimental, statistical, and numerical investigations for influence of using vegetable oil with mineral oil to enhance the flow characteristics through a closed hydraulic circuit

The aim of this paper is to investigate the performance of a hydraulic system using an equi-volume percentage of vegetable oil and mineral oil as hydraulic fluids. The hydraulic system performance was tested at different operating conditions, such as temperature and velocity. A test rig with a definite pipe length and diameter was used. The experimental results showed that the presence of vegetable oil reduced the viscosity by 21, 18, 11, and 8% at 30, 40, 50, and 60 °C, respectively. The pressure drop (ΔP) through the hydraulic circuit was improved. The reason may be attributed to a reduction in viscosity. At 6 L/min and 60 °C, the maximum percentage of drag reduction (%Dr) was around 29%, while the maximum percentage of flow improvement (%FI) was around 21%. Statistical analysis was used to correlate %Dr as a function of dimensionless groups with a high correlation coefficient. Numerical analysis was conducted using ANSYS software. Experimental and numerical results were very close with high validity. A numerical model was used to study the effect of pipe geometry. Pressure drop was increased with pipe length and inclination angle, but it decreased with pipe diameter. In the literature, the experimental and numerical performance of hydraulic systems using a blend of vegetable and mineral oils as hydraulic fluid was limited. Therefore, the current study is quite new for the hydraulic system performance at different operating conditions.

An experimental investigation on drag reduction by a combination of polymer, Laurel soap and palm fiber through circulated Newtonian liquid

Flowability and reduced pressure are some of the economic values in pipeline transportation. In this study, we investigated the functionality of self-made drag coefficients composed of a combination of large molecular weight polymer, Laurel soap, and date palm fiber which were induced into a circulated piping system under turbulent water flow. The proposed combination formulas are proved to be a new cost-effective drag reduction approach. The efficiency of using a mixture of polymer, palm fiber, and soap on the drag reduction was thoroughly evaluated via investigating several case studies. Using pure polyelectrolyte showed that at the highest polymer concentration (50 ppm), the percentage of drag reduction reaches 50% in 10.3 mm pipe diameter and 70% drag reduction in 13.5 mm pipe diameter at a flow of low Reynolds number counted 17166.7. Upon applying a mixture of polyelectrolyte composed of (50 ppm) and fiber in the range (30-60 ppm), a drag reduction of 63% in 10.3 mm pipe diameter and 76% in 13.5 mm pipe diameter were achieved, respectively. Upon examining a mixture composed of polyelectrolyte (50 ppm) and soap in a range (50-150 ppm), the results showed that the highest drag reduction was achieved at a low concentration of soap and a bulk flow at a low Reynolds number. The aforementioned performance results were exemplified attaining drag reductions of 70% in 10.3 mm pipe diameter and 96% in 13.5 mm pipe diameter, respectively. This is accomplished through optimizing the applied mixture formulas. The estimated drag reductions were shown higher when applying the polymer mixture compared to that of pure polymer. However, a slight decrease in the attained drag reductions when using polymer-soap was observed and attributed to the hindrance from the palm fiber, which ultimately reduces the chance for all soap particles to reach the stagnant wall layer

Effect of Temperature on The Performance of Naphtha and Kerosene as Viscosity Reduction Agents for Improving Flow Ability of Basrah-Iraq Heavy Crude Oil

Naphtha and kerosene are mixed with Iraqi heavy crude oil at different concentrations rounded between (3-12) wt.%, in order to reduce viscosity to enhance its followability. This research investigated drag reduction (%Dr) in heavy oil mixtures at different flow rates (2 to 10 m3/hr) in temperature range 20-50C. The experimental results proved that Naphtha offered 40% reduction in pressure drop. The Power law model was adopted in this study to empirically correlate fiction factor (f) and the percentage of drag reduction(%Dr) from experimental data for Reynolds number range (534– 14695) and the concentration range from 3 to12 wt.%.

Simulation of Crude Oil Transportation with Drag Reduction Agents Using k-ϵ and k-ω Models

This work explores the possibility of using Newtonian turbulence k−ϵ and k−ω models for modelling crude oil flow in pipelines with drag reduction agents. These models have been applied to predict the friction factor, pressure drop and the drag reduction percentage. The simulation results of both models were compared with six published experimental data for crude oil flow in pipes with different types of drag reduction agents. The velocity near the wall was determined using the log law line of Newtonian fluid equation and by changing the parameter ΔB to achieve an excellent agreement with experimental data. Simulated data for k−ϵ model shows better agreement with most experimental data than the k−ω turbulence model.

Oil-soluble organic polymer driven from aloe vera as drag reducing agent for crude oil flow in pipelines

In the present work, an organic oil-soluble drag-reducing agent (DRA) is introduced and experimentally tested. The new additive is driven from aloe vera mucilage extracted directly from the aloe vera plant. Polymer grafting process was implemented to change the solubility of the new additives from water-soluble to oil-soluble. Drag reduction solutions are prepared by mixing certain additives concentrations (200 wppm to 600 wppm) with the crude oil. Each solution was rheologically tested to examine the effect of the additives on the viscosity and viscoelastic properties of the crude oil. The drag reduction performance was examined using a closed-loop liquid circulation system specially designed and fabricated for the present work. The experimental results showed that the viscosity of the solutions decreases when the concentration of the additives increases without affecting the crude oil entity (Newtonian behaviour) with noticeable dramatic changes in the viscoelastic properties. A maximum drag reduction percentage of 82% was achieved with an additive concentration of 600 wppm. Finally, the resistance of the new additives to mechanical shear forces was high and increased exponentially with the concentration. [Received: December 5, 2019; Accepted: May 18, 2020]

Oil-soluble organic polymer driven from aloe vera as drag reducing agent for crude oil flow in pipelines

In the present work, an organic oil-soluble drag-reducing agent (DRA) is introduced and experimentally tested. The new additive is driven from aloe vera mucilage extracted directly from the aloe vera plant. Polymer grafting process was implemented to change the solubility of the new additives from water-soluble to oil-soluble. Drag reduction solutions are prepared by mixing certain additives concentrations (200 wppm to 600 wppm) with the crude oil. Each solution was rheologically tested to examine the effect of the additives on the viscosity and viscoelastic properties of the crude oil. The drag reduction performance was examined using a closed-loop liquid circulation system specially designed and fabricated for the present work. The experimental results showed that the viscosity of the solutions decreases when the concentration of the additives increases without affecting the crude oil entity (Newtonian behaviour) with noticeable dramatic changes in the viscoelastic properties. A maximum drag reduction percentage of 82% was achieved with an additive concentration of 600 wppm. Finally, the resistance of the new additives to mechanical shear forces was high and increased exponentially with the concentration. [Received: December 5, 2019; Accepted: May 18, 2020]

A numerical study on the single pulsed energy addition based unsteady wave drag reduction at varied hypersonic flow regimes

In this study, unsteady wave drag reduction in hypersonic flowfield using pulsed energy addition is numerically investigated. A single energy pulse is considered to analyze the time-averaged drag reduction/pulse. The blast wave creation, translation and its interaction with shock layer are studied. As the wave drag depends only on the inviscid aspects of the flowfield, Euler part of a well-established compressible flow Navier-Stokes solver USHAS (Unstructured Solver for Hypersonic Aerothermodynamics) is employed for the present study. To explore the feasibility of pulsed energy addition in reducing the wave drag at different flight conditions, flight Mach numbers of 5.75, 6.9 and 8.0 are chosen for the study. An [Formula: see text] apex angle blunt cone model is considered to be placed in such hypersonic streams, and steady-state drag and unsteady drag reductions are computed. The simulation results indicate that drag of the blunt-body can be reduced below the steady-state drag for a significant period of energy bubble-shock layer interaction, and the corresponding propulsive energy savings can be up to 9%. For energy pulse of magnitude 100mJ deposited to a spherical region of 2 mm radius, located 50 mm upstream of the blunt-body offered a maximum percentage of wave drag reduction in the case of Mach 8.0 flowfield. Two different flow features are found to be responsible for the drag reduction, one is the low-density core of the blast wave and the second one is the baroclinic vortex created due to the plasma energy bubble-shock layer interaction. For the same freestream stagnation conditions, these two flow features are noted to be very predominant in the case of high Mach number flow in comparison to Mach 5.75 and 6.9 cases. However, the ratio of energy saved to the energy consumed is noted as a maximum for the lower Mach number case.

Soft computing method for predicting pressure drop reduction in crude oil pipelines based on machine learning methods

In the oil industry, the drag-reducing agent has been used to reduce turbulent friction of fluids. The main effort of this study is to examine the feasibility of four novel machine learning models, namely multilayer perceptron, M5Rules, decision table (DT), and trees M5P to estimate the percentage of drag reduction. Then, the mentioned methods are utilized to identify a relationship between the input and output parameters of the crude oil pipeline system. The parameter percentage of drag reduction was taken as the essential output. In contrast, the input parameters selected the flow rate of oil, polymer concentration, kind of polymer, temperature, as well as pipe diameter and roughness. The predicted results obtained by the tools mentioned above were evaluated according to several known statistical indices, namely coefficient of determination (R2), mean absolute error (MAE), root mean squared error (RMSE), relative absolute error (RAE), and root relative squared error (RRSE) as well as novel ranking systems of color intensity rating and total ranking method. The training and testing results of the DT learning method for the R2, MAE, RMSE, RAE, and RRSE were (0.9616, 3.9008, 5.8698, 24.5259%, and 27.4406%) and (0.8964, 6.937, 10.318, 43.3841%, and 45.6581%), respectively. The obtained results, in analyzing the training and testing datasets, proved that DT is the best predictive network to predict the percentage of drag reduction.

Triple Solutions of Nanoparticle plus Polymer-Surfactant compound for Enhancing the Drag Reduction Using a Rotational Disk Apparatus

In this paper, the ability of three types of drag reduction agents (DRAs) has been investigated to assess the impact of adding a small amount part per million (ppm) of polymer and surfactant, as well as nanoparticle substances, as drag improvers of internal flow via a pipeline network. The selected DRAs have been tested in the rotating disk apparatus (RDA) at various concentrations in the range of (50-1200) ppm and various rotating disk velocities in the range of (50-3000) rpm. Multiple trials have been done to figure out the best substance for enhancing drag force reduction. Impacts of the shear rate on viscosity (μ) at various concentrations of polymer and surfactant solutions have been analyzed with rheologic tests. The results detect that all selected substances have proved to be effective drag improvers in internal flow. Torque values were decreased with increased DRA concentrations, which caused a significant increase in drag reduction percentage (%DR). The drag reduction percentage of complex solutions at the highest concentration of 1200 ppm, results in around (44-47) % DR. In contrast, the results of the individual solutions at the same concentration results in around (32-38) % DR.

Preparation and Application of Natural and Low Cost Palm Fibers as an Effective Drag Reducing Agent for Flow Improvement in Iraqi Crude Oil Pipelines

Flow of crude oil in pipelines suffers from a problem of fluid flow pressure drop and high energy consumption for fluid pumping. Flow can be enhanced using either viscosity reduction or drag reduction techniques. Drag reduction (DR) is considered as a most effective and most applicable method. The technique contributes in reducing the frictional energy losses during the flow by addition of little amounts from drag reducing agents. The present work focuses on preparation and application of a new natural and low cost material derived from palm fiber (PF) that has been tested as a drag reducing agent (DRA) for crude oil flow enhancement. This objective has been achieved through designing and constructing of an experimental rig consisting of: a crude oil pipe, oil pump, pressure sensors, solenoid valve and programmable logic control. The additive material (PF) is prepared with different diameters (75µm, 125µm, 140µm) and tested with different concentrations as: 100, 200, 300, 400, and 500 mg/L for reducing the drag inside the oil pipe. The experimental results showed that the fiber with 125µm diameter and 100ppm is the best where the percentage of drag reduction reached 43%. Furthermore, the results of this work proved that PF is an efficient and low cost DRA that can be applied successfully in crude oil pipelines as well as its contribution in the waste management.

The effect of polyacrylamide drag reducing agent on friction factor and heat transfer coefficient in laminar, transition and turbulent flow regimes in circular pipes with different diameters

In the present study, the effect of polyacrylamide (PAM) addition as a drag-reducing agent on the hydraulic and heat transfer performance of water flow inside horizontal smooth circular pipes was investigated at different heat fluxes. One of the limitations of using solutions containing drag reducing agents (DRAs) is heat transfer reduction (HTR) properties of these substances. The effect of different hydraulic and thermal factors on this phenomenon has been less systematically investigated. In this study, a large number of experiments were conducted under different operating conditions including concentrations of 50, 100, 150 ppm of PAM, inner pipe diameters of 12.7, 19.05, 25.4 mm, applied heat fluxes to pipes including 11, 15, 19 kW/m2, and fluid flowrates at the range of 0.5–20 l/min to prepare laminar, transition, and turbulent flow regimes. The maximum percentage of drag reduction (%DR) obtained at the diameter of 12.7 mm, flowrate 20 l/min, concentration 150 ppm, and at zero-wall heat flux (adiabatic condition) by 50%. By applying heat flux, the%DR decreased. Results showed that the addition of the drag reducing polymer reduces the heat transfer but applying constant heat flux to the pipe decreases the effect of polymer on the percentage of heat transfer reduction (%HTR). The maximum%HTR of 44.5% was achieved at the flowrate of 0.5 l/min and the concentration of 150 ppm and the heat flux of 11 kW/m2. Increasing pipe diameter at all the heat fluxes and polymer concentrations, decreased%DR and%HTR.

Improvement of Drag Reduction for Water Flow in Pipe Based Nanofluid

In the present work, the effect of Nano fluids as drag reducing agents for water flowing in pipelines was studied. Tap water was chosen to be the tested liquid and the Nano fluid was a dilute solution of water and titanium dioxide (TiO2) Nano particles which was used at five different concentrations (50, 100, 150, 200, and 250) ppm. The test section of the experimental setup consisted of a stainless steel pipe of 29.6 mm I.D (DN25) and 1.2 m long. Water was pumped with eight different flow rates (1.0 - 8.0 m3/hr) through the pipe at room temperature (35±1) o C. The effect of the nano particle concentration and the flow rate (or Reynolds number) on percentage drag reduction (%Dr) and flow rate increases (%FI) was examined. Generally, a gradual increase of %Dr &%FI was observed with increasing the NP concentration and bulk velocity. The highest TiO2 concentration of 250 ppm and Re.No. of 106230 offered the maximum drag reduction which was 29.7%. Friction factors were also calculated from experimental data. Their values for pure water transported lies near or at Blasuis asymptote. While by introducing the additives, their values were positioned below Blasuis asymptotes towards Virk maximum drag reduction asymptotes.

Drag Reduction and Flow Enhancement in Iraqi Crude Oil Pipelines using PMMA polymer and CNTs

Crude oil flowing in pipelines suffers from a problem fluid flow pressure drop and high energy consumption for fluid pumping. The flow can be enhanced using either viscosity reduction or drag reduction techniques. Drag reduction (DR) can be considered as the most effective and applicable method. Such method contributes in reducing the frictional energy losses during the flow by addition of little amounts of drag reducing agents (DRAs). The present work focuses on comparing between the effect of PMMA only and PMMA with CNT on drag reduction In order to achieve this object, an experimental rig has been designed and implemented. It should be mentioned that the ring consists of: a crude oil Perspex pipe, oil pump, pressure sensors. Two additive materials including PMMA and CNT with different concentrations have been used to reduce the drag inside the oil pipe. polymethyl metha acrylate polymer (PMMA) with different concentrations 1000, 2000, 3000, 4000 mg/L. It has been shown 3000ppm is the best where the percentage of drag reduction reached to 65%. While, A mixture of CNT and PMMA with (1000, 2000, 3000, 4000, 5000) mg/L are used and the results showed that 50% of DR is achieved at 2000 mg/L.