TY - JOUR
TI - Approximate expressions for the logarithmic mean void fraction
AU - Awad Mohamed M
JN - Thermal Science
PY - 2015
VL - 19
IS - 3
SP - 1135
EP - 1139
PT - Article
AB - The logarithmic mean void fraction (LMe) was introduced in literature by El  Hajal et al. (El Hajal, J., Thome, J. R., Cavallini, A., Condensation in  Horizontal Tubes, Part 1: Two-Phase Flow Pattern Map, International Journal  of Heat and Mass Transfer 46 (2003) 18, pp. 3349-3363). In the present study,  approximate expressions for the logarithmic mean void fraction (LMe) will be  presented because the original formula for the computation of the logarithmic  mean void fraction in finite precision floating-point arithmetic may suffer  from serious round-off problems when both differences (eh and era) are very  close to each other. This situation corresponds to very low values or very  high values of mass quality (x). The analogy between the logarithmic mean  temperature difference (DTLM or LMTD) in heat exchangers and the logarithmic  mean void fraction (LMe) in two-phase flow will be used. These approximations  of the LMe can be applied in the computational studies.