TY - GEN
T1 - Flow patterns and pressure drop for flow boiling inside microfinned helically coiled tube
AU - Cui, Wenzhi
AU - Li, Longjian
AU - Xin, Mingdao
AU - Jen, Tien Chien
AU - Liao, Quan
AU - Chen, Qinghua
PY - 2006
Y1 - 2006
N2 - In this paper, flow patterns and their transitions for refrigerant R134a boiling in a microfinned helically coiled tube are experimentally observed and analyzed. All the flow patterns occurred in the test can be divided into three dominant regimes, stratified-wavy flow, intermittent flow and annular flow. Experimental data are plotted in two kinds of flow maps, i.e., Taitel and Dukler flow map and mass flux versus vapor quality flow map. The transitions between various flow regimes and the differences from that in smooth straight tube have also been discussed. Martinelli parameter can be used to indicate the transition from intermittent flow to annular flow. The transition from stratified-wavy flow to annular or intermittent flow is identified in the vapor quality versus mass flux flow map. The flow regime is always in stratified-wavy flow for a mass flux less than 100 kg/(m2s). The two-phase frictional pressure drop characteristics in the test tube are also experimentally studied. The two-phase frictional multiplier data can be well correlated by Lockhart-Martinelli parameter. Considering the corresponding flow regimes, i.e., stratified and annular flow, two frictional pressure drop correlations were proposed, and showed a good agreement with the respective experimental data.
AB - In this paper, flow patterns and their transitions for refrigerant R134a boiling in a microfinned helically coiled tube are experimentally observed and analyzed. All the flow patterns occurred in the test can be divided into three dominant regimes, stratified-wavy flow, intermittent flow and annular flow. Experimental data are plotted in two kinds of flow maps, i.e., Taitel and Dukler flow map and mass flux versus vapor quality flow map. The transitions between various flow regimes and the differences from that in smooth straight tube have also been discussed. Martinelli parameter can be used to indicate the transition from intermittent flow to annular flow. The transition from stratified-wavy flow to annular or intermittent flow is identified in the vapor quality versus mass flux flow map. The flow regime is always in stratified-wavy flow for a mass flux less than 100 kg/(m2s). The two-phase frictional pressure drop characteristics in the test tube are also experimentally studied. The two-phase frictional multiplier data can be well correlated by Lockhart-Martinelli parameter. Considering the corresponding flow regimes, i.e., stratified and annular flow, two frictional pressure drop correlations were proposed, and showed a good agreement with the respective experimental data.
KW - Flow boiling
KW - Flow pattern
KW - Helically coiled tube
KW - Microfin tube
KW - Pressure drop
UR - http://www.scopus.com/inward/record.url?scp=85196508711&partnerID=8YFLogxK
U2 - 10.1115/IMECE2006-14573
DO - 10.1115/IMECE2006-14573
M3 - Conference contribution
AN - SCOPUS:85196508711
SN - 0791837904
SN - 9780791837900
T3 - American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD
BT - Proceedings of 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006 - Heat Transfer
PB - American Society of Mechanical Engineers (ASME)
T2 - 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006
Y2 - 5 November 2006 through 10 November 2006
ER -