Heat transfer to immiscible liquid mixtures in a spiral plate heat exchanger

Abstract

-This work presents new predictive correlations for heat transfer to immiscible liquid-liquid mixtures in a spiral plate heat exchanger. Liquid-liquid heat transfer studies were carried out in spiral plate heat exchangers for the water-octane, water-kerosene, and water-dodecane systems. For each composition of the mixture, the mass flow rate of the cold fluid was varied, keeping that of the hot fluid and the fluid inlet temperatures constant. Two-phase cold flow rates were in the laminar range, while the hot fluid flow was turbulent. Calculations of the LMTD (log mean temperature difference) correction factor showed that the flow was countercurrent. Heat transfer coefficients of the two-phase liquids were found to be strongly dependent on the composition of the liquid mixture and exhibited abrupt transitions as a function of the compositions. Given the absence of predictive correlations in the literature that sufficiently capture this compositiondependence, new empirical correlations were developed using part of the experimental data, with the composition of the cold fluid as an explicit variable. Statistical analysis of the regression yielded satisfactory results. The correlations were tested against the rest of the experimental data and were found to predict heat transfer coefficients within ± 15%. These preliminary studies should be useful in designing compact exchangers for handling two-phase water-organics mixtures.

Designing Spiral Plate Heat Exchangers to Extend Its Service and Enhance the Thermal and Hydraulic Performance

“…All authors have contributed in (1) the proposal and design or analysis and interpretation of the data, (2) drafting the article or revising it critically for important intellectual content and (3) the approval of the final version. This manuscript has not been submitted to, nor is under review at, another journal or other publishing institutions.…”

“…However, most of the correlations and methods explain the single-phase liquid-liquid, and as a consequence, this is not sufficiently to describe heat transfer and hydraulic behaviour, i.e., two-phase flow in spiral heat exchangers liquid-gas and liquid-vapour. Sathiyan et al [1,2] presented a study to evaluate a new equation to approximate the Nusselt number of an immiscible mixture using a countercurrent spiral heat exchanger for two-phase flow. The new correlation was based on the experimental data, and the results were agreement with the theoretical correlation.…”

Heat transfer enhancement using hybrid nanofluids in spiral plate heat exchangers

“…The thermophysical characteristic values of different nanoparticles and base fluid (water) is shown in Table 2. Equations (15)(16)(17) are applied for estimating the overall volume fraction, mass density and specific heat of the hybrid nanofluids. The subscripts bf, np, and hnf denote the base fluid, nanoparticles, and hybrid nanofluid, correspondingly.…”

“…Thirumarimurugan et al experimentally calculated effectiveness and overall heat transfer coefficients of SPHE. Later several researchers assessed the performance of SPHE by investigating the effects of flow rate, pressure drop, coil diameter, and spiral length …”

“…Later several researchers assessed the performance of SPHE by investigating the effects of flow rate, pressure drop, coil diameter, and spiral length. [14][15][16][17] With the advent of nanofluids in heat transfer applications, many researchers analyzed SPHE both numerically and experimentally using nanofluids as working medium and found improved thermal performance. [18][19][20][21][22][23][24][25][26][27][28] The reason for the enhancement in the thermal performance can be attributed to nanoparticles thermal conductivity and volume fractions.…”