Effect of Compression and Expansion on Instantaneous Heat Transfer in Reciprocating Internal Combustion Engines

Abstract

Znstantaneous heat j u x at the surface of a cylinder head in a motored diesel engine has been measured, at various speeds, using a fast-response surface thermocouple. Heat frux during compression was found to be much larger than heat flux during expansion, the maximum heat flux occurred about 8" bqore top dead centre and there was a signij-icant heat flux even when gas temperature and wall temperature were equal. During expansion, heatflowed from the surface to the gas even though the bulk gas temperature was greater than the surface temperature. These effects are predicted by solutions of the equation ofthermal energy and are shown to be related to the volumetric rate of compression or expansion. A simple modijication of Annand's equation gives good results and is recommended for general cycle calculations. The M S was receiued on 3 December 1986 and was accepted for publication on 26 the chamber surface* This fluctuation is January 1987.quite small, about 5"C, and gives a very small voltage

Local heat flux measurements in a hydrogen and methane spark ignition engine with a thermopile sensor

“…There are some doubts however about the correctness of this method. Lawton [11] and Nijeweme et al [12] have reported non-zero heat fluxes at the moment of equal wall and gas temperature.…”

Heat Transfer and Fluid Flows in Gas Springs

“…1 [1][2][3]). Attempts were made and have been reported in the literature [1,3,4] to include this phenomenon in the conventional Nu-Re model by adding a complex phasing part to the bulk gas temperature -heat transfer correlation.…”

Heat transfer during transient compression: Measurements and simulations

“…Equation (1) has been solved subject to the boundary and initial conditions using a Crank-Nicolson finite difference scheme with Gauss-Seidel iteration similar to that described by [Lawton (1987)]. The wall temperature ratio, f (t) = Tw/T∞ varies with time, principally because of the variation in T∞.…”

“…The upper estimate is for a turbulent case and uses a thermal conductivity value 25 times larger than the laminar value. Although this approach to modelling the turbulent transport is somewhat arbitrary, it was reasonably successful in the IC engine work of [Lawton (1987)] where peak heat flux values were correctly estimated to within about 10% (although discrepancies of 50% or more were typically apparent at other times during the IC engine cycle).…”