Effect of the Switching Times on the Operating Behavior of a Shockless Explosion Combustor

Abstract

In the past, a wide range of investigations are made in order to increase the efficiency gain in gas turbines by using constant volume combustion. In comparison to detonation-based concepts, such as pulse detonation engine and rotation detonation engine, a new promising way was proposed by Klein and Paschereit and firstly assessed by Bobusch et al. (Combust Sci Technol 186(10-11):1680-1689 (2014), [1]), the so-called shockless explosion combustion (SEC). The principle is based on a quasi-homogeneous auto-ignition process that leads to an approximate constant volume combustion (aCVC). In order to achieve a quasi-homogeneous auto-ignition, it is necessary to achieve constant ignition delay times along the combustor. The combustion process in the SEC is similar to the one in internal combustion engines, namely Homogeneous Charge Compression Ignition (HCCI). This paper focuses on the use of wastegates to actively control filling and flow motion in the combustor dedicated to perform quasi-homogeneous auto-ignition. The results clearly show the ability to actively control the fuel distribution and purging time in the combustor which is an important step in the evolution of the SEC.

Shock Tube and Kinetic Study on the Effects of CO2 on Dimethyl Ether Autoignition at High Pressures

“…This is achieved by the axial fuel stratification. Details about the process can be found in refs and . Since SEC is based on autoignition of the axially stratified mixture, it is highly sensitive to the local chemical-kinetic properties of the combustion mixture.…”

An alternative architecture of the Humphrey cycle and the effect of fuel type on its efficiency

“…During phase 4, the suction wave gets reflected again as a weak pressure wave at the open end and reaches the closed end of the combustor when homogeneous ignition takes place. More details on the SEC process can be found in 18,37,38 …”

“…Hydrogen is the major fuel used for pressure‐gain combustion applications 4 and is thus considered a reference fuel for the present study. Dimethyl ether (DME) was chosen as a fuel due to its excellent ignitability 37,38 and is prior use for shockless explosion combustion studies. It is a promising alternative fuel that can be produced as e‐fuel based on renewable power (PtG) 45 or from biomass 46 .…”

First law thermodynamic analysis of the recuperated humphrey cycle for gas turbines with pressure gain combustion

“…In eq.1, Q is the total heat input in the combustor, based on the lower heating value of the fuel, andṁ is the mass flow rate entering it. Dimethyl ether is used as fuel in both cycle models, due to its ignition properties and its relatively good fit for shockless explosion combustion [13,28]. The pressure at B results from eq.2, with the assumption of a calorically perfect working medium.…”

“…Shockless explosion combustion (SEC) is a pressure gain combustion concept that uses simultaneous auto-ignition in a combustible mixture. Chemical and acoustic time scales in the combustor are exploited to realize the four distinct phases of this cyclic process, which are presented in a time-space diagram in [29,11,13,28].…”