Heat Transfer Correction Methods for Turbocharger Performance Measurements

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Mario Schinnerl ◽  
Joerg Seume ◽  
Jan Ehrhard ◽  
Mathias Bogner
Keyword(s):  
Heat Transfer ◽  
Predictive Accuracy ◽  
Combustion Engine ◽  
Transfer Model ◽  
Performance Measurements ◽  
One Dimensional ◽  
Matching Process ◽  
High Speeds ◽  
Work Done ◽  
The Impact

Turbocharger performance maps used for the matching process with a combustion engine are measured on test benches which do not exhibit the same boundary conditions as the engine. However, these maps are used in engine simulations, ignoring that the compressor and turbine aerodynamic performance is rated on the basis of quantities which were measured at positions which do not coincide with the respective system boundaries of the turbomachinery. In the operating range of low to mid engine speeds, the ratio between the heat flux and the work done by the turbine and the compressor is much greater than at high speeds where heat transfer phenomena on the compressor side can usually be neglected. Heat losses on the turbine side must be taken into account even at higher shaft speeds when dealing with isentropic turbine efficiencies. Based on an extensive experimental investigation, a one-dimensional heat transfer model is developed. The compressor and turbine side are treated individually and divided into sections of inlet, wheel, outlet, diffuser, and volute. The model demonstrates the capability to properly account for the impact of heat transfer, and thereby improves the predictive accuracy of temperatures relevant for the matching process.

Heat Transfer Correction Methods for Turbocharger Performance Measurements

2016 ◽  
Author(s):  
Mario Schinnerl ◽  
Joerg Seume ◽  
Jan Ehrhard ◽  
Mathias Bogner
Keyword(s):  
Heat Transfer ◽  
Predictive Accuracy ◽  
Combustion Engine ◽  
Transfer Model ◽  
Performance Measurements ◽  
One Dimensional ◽  
Matching Process ◽  
High Speeds ◽  
Work Done ◽  
The Impact

Turbocharger performance maps used for the matching process with a combustion engine are measured on test benches which do not exhibit the same boundary conditions as the engine. However, these maps are used in engine simulations, ignoring that the compressor and turbine aerodynamic performance is rated on the basis of quantities which were measured at positions which do not coincide with the respective system boundaries of the turbomachinery. In the operating range of low to mid engine speeds, the ratio between the heat flux and the work done by the turbine and the compressor is much greater than at high speeds where heat transfer phenomena on the compressor side can usually be neglected. Heat losses on the turbine side must be taken into account even at higher shaft speeds when dealing with isentropic turbine efficiencies. Based on an extensive experimental investigation a one-dimensional heat transfer model is developed. The compressor and turbine side are treated individually and divided into sections of inlet, wheel, outlet, diffuser and volute. The model demonstrates the capability to properly account for the impact of heat transfer and thereby improves the predictive accuracy of temperatures relevant for the matching process.

scholarly journals A one-dimensional modeling study on the effect of advanced insulation coatings on internal combustion engine efficiency

2020 ◽  
pp. 146808742092158
Author(s):  
Alberto Broatch ◽  
Pablo Olmeda ◽  
Xandra Margot ◽  
Josep Gomez-Soriano
Keyword(s):  
Heat Transfer ◽  
Combustion Engine ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Insulation Material ◽  
One Dimensional ◽  
Engine Efficiency ◽  
Dimensional Modeling ◽  
The One ◽  
The Impact

This article presents a study of the impact on engine efficiency of the heat loss reduction due to in-cylinder coating insulation. A numerical methodology based on one-dimensional heat transfer model is developed. Since there is no analytic solution for engines, the one-dimensional model was validated with the results of a simple “equivalent” problem, and then applied to different engine boundary conditions. Later on, the analysis of the effect of different coating properties on the heat transfer using the simplified one-dimensional heat transfer model is performed. After that, the model is coupled with a complete virtual engine that includes both thermodynamic and thermal modeling. Next, the thermal flows across the cylinder parts coated with the insulation material (piston and cylinder head) are predicted and the effect of the coating on engine indicated efficiency is analyzed in detail. The results show the gain limits, in terms of engine efficiency, that may be obtained with advanced coating solutions.

Correcting Turbocharger Performance Measurements for Heat Transfer and Friction

2017 ◽  
Author(s):  
Mario Schinnerl ◽  
Jan Ehrhard ◽  
Mathias Bogner ◽  
Joerg Seume
Keyword(s):  
Heat Transfer ◽  
Combustion Engine ◽  
Measurement Data ◽  
Internal Heat ◽  
Friction Model ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Friction Power ◽  
Turbine Efficiency ◽  
Compressor Efficiency

The measured performance maps of turbochargers which are commonly used for the matching process with a combustion engine are influenced by heat transfer and friction phenomena. Internal heat transfer from the hot turbine side to the colder compressor side leads to an apparently lower compressor efficiency at low to mid speeds and is not comparable to the compressor efficiency measured under adiabatic conditions. The product of the isentropic turbine efficiency and the mechanical efficiency is typically applied to characterize the turbine efficiency and results from the power balance of the turbocharger. This so-called ‘thermo-mechanical’ turbine efficiency is strongly correlated with the compressor efficiency obtained from measured data. Based on a previously developed one-dimensional heat transfer model, non-dimensional analysis was carried out and a generally valid heat transfer model for the compressor side of different turbochargers was developed. From measurements and ramp-up simulations of turbocharger friction power, an analytical friction power model was developed to correct the thermo-mechanical turbine efficiency from friction impact. The developed heat transfer and friction model demonstrates the capability to properly predict the adiabatic (aerodynamic) compressor and turbine performance from measurement data obtained at a steady-flow hot gas test bench.

Overall Effectiveness of a Blade Endwall With Jet Impingement and Film Cooling

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Amy Mensch ◽  
Karen A. Thole
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Jet Impingement ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
Convective Cooling ◽  
Impingement Cooling ◽  
Internal Impingement ◽  
The Impact ◽  
Overall Effectiveness

Ever-increasing thermal loads on gas turbine components require improved cooling schemes to extend component life. Engine designers often rely on multiple thermal protection techniques, including internal cooling and external film cooling. A conjugate heat transfer model for the endwall of a seven-blade cascade was developed to examine the impact of both convective cooling and solid conduction through the endwall. Appropriate parameters were scaled to ensure engine-relevant temperatures were reported. External film cooling and internal jet impingement cooling were tested separately and together for their combined effects. Experiments with only film cooling showed high effectiveness around film-cooling holes due to convective cooling within the holes. Internal impingement cooling provided more uniform effectiveness than film cooling, and impingement effectiveness improved markedly with increasing blowing ratio. Combining internal impingement and external film cooling produced overall effectiveness values as high as 0.4. A simplified, one-dimensional heat transfer analysis was used to develop a prediction of the combined overall effectiveness using results from impingement only and film cooling only cases. The analysis resulted in relatively good predictions, which served to reinforce the consistency of the experimental data.

One-Dimensional Zonal Model for the Unsteady Heat Transfer Analysis in an Open Volumetric Air Receiver

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Gurveer Singh ◽  
Vishwa Deepak Kumar ◽  
Laltu Chandra ◽  
R. Shekhar ◽  
P. S. Ghoshdastidar
Keyword(s):  
Heat Transfer ◽  
High Heat ◽  
Operating Conditions ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
High Heat Flux ◽  
Unsteady Heat Transfer ◽  
Volumetric Heating ◽  
One Dimensional ◽  
Zonal Model

Abstract The open volumetric air receiver (OVAR)-based central solar thermal systems provide air at a temperature > 1000 K. Such a receiver is comprised of porous absorbers, which are exposed to a high heat-flux > 800 Suns (1 Sun = 1 kW/m2). A reliable assessment of heat transfer in an OVAR is necessary to operate such a receiver under transient conditions. Based on a literature review, the need for developing a comprehensive, unsteady, heat transfer model is realized. In this paper, a seven-equations based, one-dimensional, zonal model is deduced. This includes heat transfer in porous absorber, primary-air, return-air, receiver casing, and their detailed interaction. The zonal model is validated with an inhouse experiment showing its predictive capability, for unsteady and steady conditions, within the reported uncertainty of ±7%. The validated model is used for investigating the effect of operating conditions and absorber geometry on the thermal performance of an absorber. Some of the salient observations are (a) the maximum absorber porosity of 70–90% may be preferred for non-volumetric and volumetric-heating conditions, (b) the minimum air-return ratio should be 0.7, and (c) the smallest gap to absorber-length ratio of 0.2 should suffice. Finally, suggestions are provided for extending the model.

scholarly journals Mathematical Modeling of Heat Transfer in an Element of Combustible Plant Material When Exposed to Radiation from a Forest Fire

Safety ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 56 ◽  
Author(s):  
Nikolay Baranovskiy ◽  
Alena Demikhova
Keyword(s):  
Heat Transfer ◽  
Forest Fire ◽  
Forest Fires ◽  
Plant Material ◽  
Mathematical Physics ◽  
Burned Area ◽  
Herbaceous Plant ◽  
One Dimensional ◽  
Impact Prediction ◽  
The Impact

The last few decades have been characterized by an increase in the frequency and burned area of forest fires in many countries of the world. Needles, foliage, branches, and herbaceous plants are involved in burning during forest fires. Most forest fires are surface ones. The purpose of this study was to develop a mathematical model of heat transfer in an element of combustible plant material, namely, in the stem of a herbaceous plant, when exposed to radiation from a surface forest fire. Mathematically, the process of heat transfer in an element of combustible plant material was described by a system of non-stationary partial differential equations with corresponding initial and boundary conditions. The finite difference method was used to solve this system of equations in combination with a locally one-dimensional method for solving multidimensional tasks of mathematical physics. Temperature distributions were obtained as a result of modeling in a structurally inhomogeneous stem of a herbaceous plant for various scenarios of the impact of a forest fire. The results can be used to develop new systems for forest fire forecasting and their environmental impact prediction.

Heat Transfer on a Turbocharger Under Constant Load Points

2009 ◽  
Author(s):  
A. Romagnoli ◽  
Ricardo Martinez-Botas
Keyword(s):  
Heat Transfer ◽  
Combustion Engine ◽  
Constant Load ◽  
Heat Transfer Process ◽  
Transfer Model ◽  
Performance Deterioration ◽  
Exit Temperature ◽  
Standard Set ◽  
Compressor Performance ◽  
Compressor Efficiency

The processes occurring in turbo machinery applications are frequently treated as adiabatic. However, in a turbocharger significant heat transfer occurs, leading to a deficit of turbocharger performance. The overall objective of this experimental work is to improve the understanding of the heat transfer process taking place in a turbocharger when installed on an internal combustion engine. In order to do this, beyond the standard set of measurements needed to define the turbo operating point, a large number of thermocouples were installed on the turbocharger. The tests results allow the quantification of the temperatures within the turbocharger and revealed that a nonuniform temperature distribution exists on the compressor and turbine casings. This is partly attributed to the proximity of the turbocharger to the engine. This process plays a role on the deterioration of the compressor efficiency when compared to the corresponding adiabatic efficiency. A correlation that allows the calculation of the compressor exit temperature is proposed. The method uses the surface temperature of the bearing housing; it was validated against experimental data with deviations no larger than 3%. A simplified 1-dimensional heat transfer model was also developed and compared with experimental measurements. The algorithms calculate the heat transferred through the turbocharger, from the hot end to the cold end by means of lump masses. The compressor performance deterioration from the adiabatic map is predicted.

Thermal Accumulation in Metal Micro-Parts Fabricated by Micro Droplet Deposition Manufacturing Technique

2014 ◽  
Vol 941-944 ◽  
pp. 2154-2157
Author(s):  
Han Song Zuo ◽  
He Jun Li ◽  
Le Hua Qi ◽  
Jun Luo ◽  
Song Yi Zhong
Keyword(s):  
Heat Transfer ◽  
Processing Parameters ◽  
Transfer Model ◽  
Droplet Deposition ◽  
One Dimensional ◽  
Input And Output ◽  
Deposit Surface ◽  
Micro Parts ◽  
Thin Walled ◽  
Deposit Height

Thermal accumulation in micro droplet deposition manufacturing (MDDM) has a significant influence on geometric profile and microstructure of the fabricated metal micro-parts. In this paper, thermal behavior of a new aluminum droplet on the deposit surface was investigated using one-dimensional heat transfer model. Then several thin-walled aluminum cubic pipes were fabricated by MDDM to verify the numerical analysis result. The result shows that the thermal accumulation would increase gradually with the increase of the deposit height. It associated with thermal input and output on the top surface of the deposit, which could be controlled or eliminated by optimizing processing parameters such as deposition frequency.

scholarly journals Three-dimensional effects in polarization signatures as observed from precipitating clouds by low frequency ground-based microwave radiometers

2006 ◽  
Vol 6 (3) ◽  
pp. 5427-5456
Author(s):  
A. Battaglia ◽  
C. Simmer ◽  
H. Czekala
Keyword(s):  
Radiative Transfer ◽  
Monte Carlo Model ◽  
Three Dimensional ◽  
Low Frequency ◽  
Radiative Transfer Model ◽  
Observation Angle ◽  
Transfer Model ◽  
One Dimensional ◽  
Dimensional Effects ◽  
The Impact

Abstract. Consistent negative polarization differences (i.e. differences between the vertical and the horizontal brightness temperature) are observed when looking at precipitating systems by ground-based radiometers at slant angles. These signatures can be partially explained by one-dimensional radiative transfer computations that include oriented non-spherical raindrops. However some cases are characterized by polarization values that exceed differences expected from one-dimensional radiative transfer. A three-dimensional fully polarized Monte Carlo model has been used to evaluate the impact of the horizontal finiteness of rain shafts with different rain rates at 10, 19, and 30 GHz. The results show that because of the reduced slant optical thickness in finite clouds, the polarization signal can strongly differ from its one-dimensional counterpart. At the higher frequencies and when the radiometer is positioned underneath the cloud, significantly higher negative values for the polarization are found which are also consistent with some observations. When the observation point is located outside of the precipitating cloud, typical polarization patterns (with troughs and peaks) as a function of the observation angle are predicted. An approximate 1-D slant path radiative transfer model is considered as well and results are compared with the full 3-D simulations to investigate whether or not three-dimensional effects can be explained by geometry effects alone. The study has strong relevance for low-frequency passive microwave polarimetric studies.

Under Pressure Welding and Preheat Temperature Decay Times on Carbon Dioxide Pipelines

2014 ◽  
Author(s):  
Simon Slater ◽  
Robert Andrews ◽  
Peter Boothby ◽  
Julian Barnett ◽  
Keith Armstrong
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Natural Gas ◽  
Cooling Rate ◽  
Gaseous Phase ◽  
Transfer Model ◽  
Dense Phase ◽  
Pressure Welding ◽  
One Dimensional ◽  
Decay Times

Whilst there is extensive industry experience of under pressure welding onto live natural gas and liquid pipelines, there is limited experience for Carbon Dioxide (CO2) pipelines, either in the gaseous or dense phases. National Grid has performed a detailed research programme to investigate if existing natural gas industry under pressure welding procedures are applicable to CO2 pipelines, or if new specific guidance is required. This paper reports the results from one part of a comprehensive trial programme, with the aim of determining the preheat decay times, defined by the cooling time from 250 °C to 150 °C (T250–150), in CO2 pipelines and comparing them to the decay times in natural gas pipelines. Although new build CO2 pipelines are likely to operate in the dense phase, if an existing natural gas pipeline is converted to transport CO2 it may operate in the gaseous phase and so both cases were considered. The aims of the work presented were to: • Determine the correlations between the operating parameters of the pipeline, i.e. flow velocity, pressure etc. and the cooling rate after removal of the preheat, characterised by the (T250–150) cooling time. • Compare the experimentally determined T250–150 cooling times with the values determined using a simple one dimensional heat transfer model. • Define the implications of heat decay for practical under pressure welding on CO2 pipelines. Small-scale trials were performed on a 150 mm (6″) diameter pressurised flow loop at Spadeadam in the UK. The trial matrix was determined using a one dimensional heat transfer model. Welding was performed on a carbon manganese (C-Mn) pipe that was machined to give three sections of 9.9 mm, 19.0 mm and 26.9 mm wall thickness. Trials were performed using natural gas, gaseous phase CO2 and dense phase CO2; across a range of flow velocities from 0.3 m/s to 1.4 m/s. There was relatively good agreement between the T250–150 cooling times predicted by the thermal model and the measured T250–150 times. For the same pipe wall thickness, flow velocity and pressure level, the preheat decay cooling times are longest for gaseous phase CO2, with the fastest cooling rate recorded for dense phase CO2. Due to the fast cooling rate observed on dense phase CO2, the T250–150 times drop below the 40 second minimum requirement in the National Grid specification for under pressure welding, even at relatively low flow velocities. The practical limitation for under pressure welding of pipelines containing dense phase CO2 will be maintaining sufficient preheating during welding. The results from this stage of the technical programme were used to develop the welding trials and qualification of a full encirclement split sleeve assembly discussed in an accompanying paper (1).

Sign in / Sign up

Export Citation Format

Share Document