The Onset of Flow Instability in Uniformly Heated Horizontal Microchannels

TLDR

The study experimentally investigated nucleate boiling and flow instability in uniformly heated microchannels using 22‑cm long tubular sections of 1.17 mm and 1.45 mm diameter, varying channel exit pressure (3.44–10.34 bar), mass flux (800–4500 kg m⁻² s⁻¹), wall heat flux (0–4.0 MW m⁻²), and Peclet number (7440–33 000) to generate demand curves for onset determination. Onset data for nucleate boiling and flow instability were obtained and compared with widely used correlations. Article identifier: S0022-1481(00)02101-0.

Abstract

Abstract Onset of nucleate boiling and onset of flow instability in uniformly heated microchannels with subcooled water flow were experimentally investigated using 22-cm long tubular test sections, 1.17 mm and 1.45 mm in diameter, with a 16-cm long heated length. Important experimental parameter ranges were: 3.44 to 10.34 bar channel exit pressure; 800 to 4500 kg/m2s mass flux (1 to 5 m/s inlet velocity); 0 to 4.0 MW/m2 channel wall heat flux; and 7440–33,000 Peclet number at the onset of flow instability. Demand curves (pressure drop versus mass flow rate curves for fixed wall heat flux and channel exit pressure) were generated for the test sections, and were utilized for the specification of the onset of nucleate boiling and the onset of flow instability points. The obtained onset of nucleate boiling and onset of flow instability data are presented and compared with relevant widely used correlations. [S0022-1481(00)02101-0]