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The purpose of this study is analysis on fluid flow characteristics inside a modified designed spiral bubble column photo-bioreactor. Available fluid dynamic simulation of bubble column reactor (BCR) (which is well-known conventional photobioreactor) had shown significance contribution over the past two decades, where the fluid dynamics of the culture medium and mixing will influence the average irradiance and the light regimen to which the cells are exposed. This enhances the growth. To develop this, and also to cut down the cost parameter involving the production of biodiesel from algae, the growth rate of algae has to be enhanced.

Some design modification through a staggered spiral-path inside the bubble column design had been proposed and comparative simulation of the modified design has been reported. Three-dimensional simulations of gas–liquid flow both in the BCR and spiral path column reactor have been carried out using the Euler–Euler approach. Various graphs are plotted, and from comparing, it has been seen that the proposed reactor will enhance better mixing rate, which could help the growth rate in microalgae in the present proposed model. In this paper, an earnest attempt had made to carry out computational simulation of conventional BCR and designed reactor used for cultivation of microalgae which had analyzed using commercial code ANSYS 14.

From this work, it was observed that the average turbulence kinetic energy fluctuates more in designed reactor over the conventional photo bioreactor, which will in turn increase diffusivity and enhance transfer of mass, momentum and energy. The results provide comprehensive information concerning effect of fluid flow characteristics inside a modified designed spiral bubble-column photo-bioreactor.

Some of our earlier published results (www.scientific.net/AMM.592-594.2427) are also referred in this paper. This work had been performed under the financial aid from RPS project (no. 8,023/RID/RPS/27/11/12), sponsored by All India Council for Technical Education.

The heat transfer within a heat exchanger is highly influenced by geometry of the components especially those with hollow structures like tubes. This paper aims to intend toward the study of efficient and optimized heat transfer in the bends of superheater tubes, with different curvature ratio at constant Reynolds Number.

The effect of changing curvature ratio on enthalpy of the fluid passing through the superheater tubes for multi-pass system has been studied with the aid of computational fluid dynamics (CFD) using ANSYS 14.0. Initially a superheater tube with two pass system has been examined with different curvature ratios of 1.425, 1.56, 1.71, 1.85 and 1.99. An industry specified curvature ratio of 1.71 with two pass is investigated, and a comparative assessment has been carried out. This is intended toward obtaining an optimized radius of curvature of the bend for enhancement of heat transfer.

The results obtained from software simulation revealed that the curvature ratio of 1.85 provides maximum heat transfer to the fluid flowing through the tube with two pass. This result has been found to be consistent with higher number of passes as well. The effect of secondary flow in bends of curvature has also been illustrated in the present work.

The study of heat transfer in thermodynamic systems is a never-ending process and has to be continued for the upliftment of power plant performances. This study has been conducted on steady flow behavior of the fluid which may be upgraded by carrying out the same in transient mode. The impact of different curvature ratios on some important parameters such as heat transfer coefficients will certainly upgrade the value of research.

This computational study provided comprehensive information on fluid flow behavior and its effect on heat transfer in bends of curvature of superheater tubes inside the boiler. It also provides information on optimized bend of curvature for efficient heat transfer process.