Experimental study on heat transfer and pressure drop characteristics of air–water two-phase flow with the effect of polyacrylamide additive in a horizontal circular tube

Applications of Water-Soluble Polymers in Turbulent Drag Reduction

“…Although PAAM produced a much higher initial DR value, this drag reduction effect decreased to zero in 5 min. Zhang et al [63] experimentally investigated heat transfer and frictional DR in the two-phase flow of air-water with and without PAAM additives in a horizontal circular tube. They showed that with the addition of PAAM, the heat transfer coefficients were reduced from 36.8% to 70.3%, and the pressure drop was reduced from 31.9% to 54.7% compared to those without the PAAM additive.…”

Water Soluble Polymers

“…To show that a block copolymer consisting of one block of pH-tunable poly(MAA/2VP) could be made with a second block of cloud-point temperature (CPT) tunable poly(4AM/4AP), a chain extension experiment was done with a typical poly(tBMA-stat-2VP) macroinitiator (tBMA/2VP-50) and a batch of 4AM/4AP at a composition that would give a CPT of about 35 • C in a 1 wt% aqueous solution [63]. We understand that the CPT could be altered by the nature of the other segment as it can be moved to lower or higher temperatures (or even extinguished entirely) depending on the composition of the other block.…”

“…The composition of 4AM/4AP was chosen so that a clearly defined CPT~35 • C could be observed, as we found in our previous study [63]. There was some unreacted macroinitiator but it was readily removed by subsequent fractionation (see Figure 4).…”

“…To circumvent this issue, MAA or acrylic acid (AA) NMP was done with the addition of a small amount of free nitroxide, which was essentially sacrificed to keep the chain ends active throughout the polymerization [48,61,62]. The poly(2VP-stat-tBMA) copolymers were then used as macroinitiators for a tunable, thermo-responsive segment of poly(acryloyl piperidine-ran-acryloyl-morpholine) (4AP-stat-4AM), which we reported recently [63]. We thus present the synthesis of a dual responsive (pH and temperature) block copolymer where the respective blocks' response could be tuned by its composition (tBMA versus 2VP for pH tuning; 4AP versus 4AM for cloud point tuning).…”

Experimental study of the effect of drag reducing agent on pressure drop and thermal efficiency of an air cooler

“…Kim et al [28] and Yoon et al [29] examined the rates of drag reduction and also the degradation effects in a synthetic polymer solution with surfactant additives. Zhang et al [30] carried out experiments on heat transfer and frictional pressure drop using two phase flow of air-water with and without polyacrylamide (PAM) additive in a horizontal smooth circular tube. They showed that the two phase pressure drop can be reduced to 55 % while the two phase heat transfer coefficient can be reduced to 70 % with the PAM additive.…”