Sandro Gierth

CADFEM Germany GmbH

The synthetic diesel fuel (Poly-)oxymethylene ether (OME) has various interesting properties for the transport sector. OME reduces emissions in direct injection (DI) diesel engines, e.g., soot and NO , and is considered CO2 neutral. While most studies have examined a mixture of OMEs with different chain lengths, recent studies have focused on neat...

A systematic analysis of knocking combustion at the knock limit in a single-cylinder research engine is conducted. Both experimental and numerical methods are used to investigate the physical phenomena involved in knocking combustion. While real gasoline fuel can be used directly in experimental studies, this is not feasible in numerical simulation...

Accurate knowledge of the boundary layer in an Internal Combustion Engine (ICE) is necessary to increase engine efficiency [1] and for improved modeling of the engine flows [2]. Inside the cylinder of an ICE, the flow is highly complex, characterized by turbulent core flow [3] and pressure gradient along the walls [4]. The boundary layer observed i...

The Method of Moments (MOM) has largely been applied to investigate sooting laminar and turbulent flames. However, the classical MOM is not able to characterize a continuous particle size distribution (PSD). Without access to information on the PSD, it is difficult to accurately take into account particle oxidation, which is crucial for shrinking a...

The occurrence of knocking combustion is limiting the efficiency of modern spark ignition engine operation. Thus, an understanding of the processes at the knock limit is required for further optimization of the combustion process. In this work, the combustion of a multicomponent Toluene Reference Fuel (TRF) in a single-cylinder research engine is i...

The Method of Moments (MOM) has largely been applied to investigate sooting laminar and turbulent flames. However, the classical MOM is not able to characterize a continuous particle size distribution (PSD). Without access to information on the PSD, it is difficult to accurately take into account particle oxidation, which is crucial for shrinking a...

The ignition of non-premixed n-dodecane-air flames is studied in a highly transient counterflow configuration under diesel engine operating conditions. The one-dimensional transient counterflow is configured such that ignition is initially physically inhibited through high strain rates. In a short relaxation period the inflow velocities (thereby th...

Within the Unsteady Flamelet Progress Variable – Large Eddy Simulation (UFPV-LES) approach the local scalar dissipation rate represents one key parameter, significantly affecting the ignition behaviour. In this study, the UFPV-LES approach is evaluated for ECN Spray A baseline conditions, relevant for diesel engines. After confirming its general ap...

This article reports on a novel design of an AdBlue mixing unit to reduce urea deposits at low temperatures in diesel exhaust. The main principle of the mixer includes the injection of AdBlue in an axisymmetric swirling flow, which is achieved by splitting the exhaust stream and off‐centred introduction of the sub‐flows. Crucial geometric parameter...

In this work, large-eddy simulations (LESs) are conducted for a multiple-injection flame in a diesel engine environment using an unsteady flamelet/progress variable (UFPV) approach in which differential diffusion is considered. The suitability of the UFPV tabulation approach is first evaluated through a priori analyses using the state-of-the-art di...

We propose a 3D simulation method for the description of the engine cause-and-effect chain originating from in-nozzle flow via injection, atomization, mixture formation, ignition and combustion up to the emission formation. We provide highly-resolved reference solutions by a High-Performance-Computing (HPC) method. In the HPC method turbulence is t...

The modeling of differential diffusion in flamelet-based approaches is analyzed in a turbulent non-premixed oxy-fuel flame experimentally investigated by Sevault et al. (2012). The flamelet models considered are the unity Lewis number flamelet (ULNF) model proposed by Peters (1986), the variable Lewis number flamelet (VLNF) model presented by Pitsc...