Experiments on and thermodynamic analysis of a turbocharged engine with producer gas as fuel

Abstract

This article presents the studies conducted on turbocharged producer gas engines designed originally for natural gas (NG) as the fuel. Producer gas, whose properties like stoichiometric ratio, calorific value, laminar flame speed, adiabatic flame temperature, and related parameters that differ from those of NG, is used as the fuel. Two engines having similar turbochargers are evaluated for performance.Detailed measurements on the mass flowrates of fuel and air, pressures and temperatures at various locations on the turbocharger were carried out. On both the engines, the pressure ratio across the compressor was measured to be 1.40 AE 0.05 and the density ratio to be 1.35 AE 0.05 across the turbocharger with after-cooler. Thermodynamic analysis of the data on both the engines suggests a compressor efficiency of 70 per cent. The specific energy consumption at the peak load is found to be 13.1 MJ/kWh with producer gas as the fuel. Compared with the naturally aspirated mode, the mass flow and the peak load in the turbocharged after-cooled condition increased by 35 per cent and 30 per cent, respectively. The pressure ratios obtained with the use of NG and producer gas are compared with corrected mass flow on the compressor map.

Selection and thermodynamic analysis of a turbocharger for a producer gas-fuelled multi-cylinder engine

“…The variation of the actual compressor inlet and exit temperature, the isentropic exit temperature and the isentropic efficiency with load is shown in Figure 16. The maximum isentropic efficiency is 74.5% and is in line with literature reported values of around 75% 11,10 and the identified efficiency on the compressor map (refer Figure 2). Dasappa et al.…”

“…The actual exit temperature is estimated using equation (4) assuming isentropic efficiency of 75%. 9,32,10 The initial pressure ratio is corrected to account for the temperature rise by using the equation of state as in equation (5). The pseudo mass flow parameter and the corresponding pressure ratio for the 50% to 100% load range are listed in Table 4 …”

“…This is compounded further by the limited availability of dedicated engines for bio-derived alternative fuels, 9 forcing the unmodified use of engines designed for conventional fuels. Fuelling of unmodified conventional fuel engines with alternative fuels introduces power de-rating 10 as one of the primary penalties. Engine de-rating leads to higher cost per kWh for the energy produced 11,12 and an increase in the capital cost per kW rating, 13,14 adversely affecting the economics of power generation.…”

“…The diesel and NG data are from CIL specifications while the data for PG-fuelled turbocharged after-cooled (TA) operation have been reported by Dasappa et al. 9,10 The detailed engine specifications and performance with the three fuels are tabulated in Tables 9–11 in the Appendix 2. The critical results are consolidated and presented as a bar chart in Figure 1.…”

“…Literature survey indicates very limited fundamental work on PG engines, with most of the literature being primarily on the performance analysis of PG-fuelled engines. 9,10,25–27 The authors find no work that holistically analyses and quantifies the various de-rating components and suggests suitable strategy for power recovery.…”