Preliminary Experimental Study on Pressure Loss Coefficients of Exhaust Manifold Junction

Xiao-Lu Lu,Kun Zhang,Shao-Ming Wang,Wen-Hui Wang,Kang-Yao Deng

doi:10.1155/2014/316498

Abstract

The flow characteristic of exhaust system has an important impact on inlet boundary of the turbine. In this paper, high speed flow in a diesel exhaust manifold junction was tested and simulated. The pressure loss coefficient of the junction flow was analyzed. The steady experimental results indicated that both of static pressure loss coefficientsL13andL23first increased and then decreased with the increase of mass flow ratio of lateral branch and public manifold. The total pressure loss coefficientK13always increased with the increase of mass flow ratio of junctions 1 and 3. The total pressure loss coefficientK23first increased and then decreased with the increase of mass flow ratio of junctions 2 and 3. These pressure loss coefficients of the exhaust pipe junctions can be used in exhaust flow and turbine inlet boundary conditions analysis. In addition, simulating calculation was conducted to analyze the effect of branch angle on total pressure loss coefficient. According to the calculation results, total pressure loss coefficient was almost the same at low mass flow rate of branch manifold 1 but increased with lateral branch angle at high mass flow rate of branch manifold 1.

Highlights

A very substantial part of the design of a turbocharging system is the exhaust pipe construction
The total pressure loss coefficient K13 always increased with the increase of the flow ratio between branch manifold 1 and branch manifold 3
The high speed flow in a diesel exhaust manifold 45∘ junction was tested, and three junctions with different lateral branch angles were simulated by CFD analysis software

Summary

Introduction

A very substantial part of the design of a turbocharging system is the exhaust pipe construction. This is because the flow characteristic of the exhaust system has an important impact on the inlet boundary of the turbine, which affects the power out of the turbine. By using a numerical simulation, it is possible to understand the exhaust pipe pressure wave forms and their propagation characteristics and analyze the use of the exhaust energy and cylinder scavenging as well as design and optimization of the exhaust system. There are three-dimensional flows in the exhaust manifold junction of the exhaust pipe system; so, using a one-dimensional numerical simulation will result in a large error. Accuracy in the pressure loss coefficient simulation of the exhaust manifold junction of the exhaust pipe system is essential. During the existing one-dimensional simulation of the engine, when the exhaust gas passes with a higher flow rate, the accuracy of the calculated pressure loss of the tee is relatively low

Methods

Results

Conclusion