The influence of the intake manifold diameter on non-stationary gas dynamics and heat transfer of pulsating flows as applied to a piston engine

Аuthors

Plotnikov L. V.^*, Plotnikov O. A., Sergeev G. D.

Ural Federal University named after the first President of Russia B.N. Yeltsin, 19, Mira str., Ekaterinburg, 620002, Russia

*e-mail: leonplot@mail.ru

Abstract

Improving the design of the main systems of piston engines remains an urgent task in order to improve their technological and environmental performance. The article examines the influence of the internal diameter of the manifold on the flow turbulence number Tu, air flow rate and heat transfer coefficient of pulsating air flows in the intake system of a piston engine based on laboratory experiments. The stand, features of the experiments and the measuring system are described in the article. The thermal anemometry method was used to obtain data on the local air flow velocity and the local heat transfer coefficient in the intake manifold. Three designs of manifolds with internal diameters of 26 mm, 32 mm (base) and 40 mm were studied. The average velocity of the pulsating air flow in the manifolds was from 5,5 to 40 m/s. Flow pulsations ranged from 5 Hz to 25 Hz (the engine crankshaft rotation frequency varied in the range from 600 rpm to 3000 rpm). It was shown that the size of the manifold diameter has a significant effect on the gas-dynamic and heat-exchange characteristics of the flows in the engine intake system. It is established that an increase in the manifold diameter (from 26 mm to 40 mm) causes a decrease in the turbulence number by 1,4–2,2 times (from Tu = 0,26–0,4 to Tu = 0,12–0,25) in the intake system. It is shown that air consumption through the intake system increases by 5–28 % with an increase in the manifold diameter from 26 mm to 40 mm. Data on the influence of the manifold diameter on the heat transfer intensity in the intake system from the crankshaft speed and the average flow velocity are presented. The difference of the change in the Nusselt number on the Reynolds number of pulsating flows in the intake system with manifolds of different diameters are obtained. The obtained data on gas dynamics and heat exchange of pulsating gas flows in intake systems can be useful for improving the quality of mathematical models and developing efficient and accurate control systems for gas exchange processes in piston engines. 

Keywords:

piston engine, intake process, manifold diameter, non-stationary gas dynamics, turbulence number, heat transfer, air consumption