This paper describes the characteristics of heat transfer and flow around several spacers (a single row of several cylindrical rods) in cross flow on a heated surface in a parallel plate duct. Temperature distributions are obtained by using a thermosensitive liquid crystal film and a narrow band optical filter method that does not require human color perception. Apparent local Nusselt numbers between two cylindrical rods are expressed as a function of Reynolds number, local position and pitch of the cylindrical rods. The pitch and Reynolds number affect the wake flow patterns which are classified into three domains.