Two-Phase Flow on the Shell-Side of a Segmentally Baffled Shell-and-Tube Heat Exchanger

Abstract

This paper reviews work carried out at the National Engineering Laboratory, UK., related to pressure drop flow patterns and phase distribution on the shell-side of segmentally baffled shell-and-tube heat exchangers. The experimental work reported was carried out using air/water mixtures in model exchangers of rectangular cross section with tube nests containing approximately 40 tubes. Data were obtained on crossflow pressure drop and on the pressure drop attributable to the windows. In certain configurations the void fraction and flow pattern maps were obtained. The geometric conditions examined related to configurations appropriate to operation as condensers and boilers. Correlations for pressure drop and void fraction were developed and flow pattern maps obtained.

Two-phase pressure drop during upward cross flow in triangular tube bundle

“…1, the frictional pressure drop [11] presents the highest percentage of data within an error band of ±30%, with 54% of predictions within this error band. Similarly, the method of Grant and Chisholm [16] assuming gravitational pressure drop given by Schrage et al [11] method gives better predictions than the others combinations, with 50% of data within ±30%, however it gives high mean absolute error.…”

“…Grant and Chisholm [16] Ishihara et al [17] Schrage et al [11] Xu et al [13] Homogeneous model Dowlati et al [15] Grant and Chisholm [16] Ishihara et al [17] Schrage et al [11] Experimental results for pressure drop during twophase flow were presented. For reduced liquid superficial velocities, the total pressure drop decreases with increasing the superficial gas velocity, due to the reduction of the gravitational pressure drop parcel.…”

“…Xu et al [13] Homogeneous model 0 Predictive methods for void fraction and frictional pressure drop parcel were evaluated. Best predictions of the total pressure drop were provided by the combinations of homogeneous model and Grant and Chisholm [16] predictive methods for frictional pressure drop with the void fraction predictive method proposed by Schrage et al [11]. Nonetheless, for pressure drop estimative during two-phase flow across tube bundles.…”

Numerical Study of Flow Separation and Pressure Drop for Flow Past Staggered Tube Bundles

“…void fraction transients. The visual observations is used by [6] to study the flow regimes of vertical air-water flow across horizontal tube bundles in a segmental baffled heat exchanger consisting of 39 tubes, 19 mm in outside diameter, arranged in an in-line configuration with a pitch to diameter ratio of 1.25. Upward flow could be described as either bubbly, intermittent, or spray flow, whereas downward flow could be described as bubbly, stratified and stratified-spray or spray flow.…”

Estudo teórico e experimental sobre padrões de escoamento, fração de vazio e perda de pressão durante escoamento bifásico água-ar cruzado ascendente externo a banco de tubos

“…A identificação subjetiva foi realizada através da observação visual do escoamento através das paredes transparentes do modelo de trocador de calor, enquanto que a identificação objetiva foi realizada a partir da análise do número e diâmetro de bolhas, determinados a partir de imagens fotográficas. Xu et al (1998b) descrevem os padrões para escoamento cruzado ascendente de forma similar a Grant e Chisholm (1979), exceto pelo padrão de escoamento agitante (churn flow). Xu et al (1998b) …”