Simultanous Transient Surface Temperature and Heat Flux Measurements in a Large Bore Two-Stroke Diesel Engine

2012 ◽  
Author(s):  
Caspar Ask Christiansen ◽  
Stefan Mayer ◽  
Jesper Schramm
Keyword(s):  
Heat Flux ◽  
Diesel Engine ◽  
Surface Temperature ◽  
Three Dimensional ◽  
Fast Response ◽  
High Temporal Resolution ◽  
Measure Surface Temperature ◽  
Flux Measurements ◽  
Surface Thermocouple ◽  
Cyclic Surface

Surface temperature measurements were performed in a large bore two-stroke diesel engine used for ship propulsion. A specially designed fast-response surface thermocouple was used together with an embedded standard K-type thermocouple to measure surface temperature and heat flux with high temporal resolution. Heat flux calculations were carried out both analytically and numerically showing good agreement between the results. Measurements were carried out at three different engine load conditions (25%, 30% and 50% load) in one of the fuel atomizers in the cylinder head. Cyclic surface temperature variations of up to approximately 80 K with a peak temperature of 860 K were observed. The magnitude of the perturbation of the temperature field due to the presence of the thermocouples was investigated by three dimensional CFD simulations.

High-output diesel engine heat transfer: Part 1 - comparison between piston heat flux and global energy balance

2021 ◽  
pp. 146808742110170
Author(s):  
Eric Gingrich ◽  
Michael Tess ◽  
Vamshi Korivi ◽  
Jaal Ghandhi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Diesel Engine ◽  
Surface Temperature ◽  
Fast Response ◽  
Temperature Data ◽  
Start Of Injection ◽  
Local Measurements ◽  
Surface Temperature Data ◽  
High Output

High-output diesel engine heat transfer measurements are presented in this paper, which is the first of a two-part series of papers. Local piston heat transfer, based on fast-response piston surface temperature data, is compared to global engine heat transfer based on thermodynamic data. A single-cylinder research engine was operated at multiple conditions, including very high-output cases – 30 bar IMEPg and 250 bar in-cylinder pressure. A wireless telemetry system was used to acquire fast-response piston surface temperature data, from which heat flux was calculated. An interpolation and averaging procedure was developed and a method to recover the steady-state portion of the heat flux based on the in-cylinder thermodynamic state was applied. The local measurements were spatially integrated to find total heat transfer, which was found to agree well with the global thermodynamic measurements. A delayed onset of the rise of spatially averaged heat flux was observed for later start of injection timings. The dataset is internally consistent, for example, the local measurements match the global values, which makes it well suited for heat transfer correlation development; this development is pursued in the second part of this paper.

Fast-Response transient heat flux measurements in a plasma wind tunnel

2021 ◽  
Vol 173 ◽  
pp. 121234
Author(s):  
Byrenn Birch ◽  
David Buttsworth ◽  
Stefan Löhle ◽  
Fabian Hufgard
Keyword(s):  
Heat Flux ◽  
Wind Tunnel ◽  
Fast Response ◽  
Flux Measurements ◽  
Transient Heat Flux

Heat transfer of three-dimensional micropolar fluid on a Riga plate

2020 ◽  
Vol 98 (1) ◽  
pp. 32-38 ◽  
Author(s):  
S. Nadeem ◽  
M.Y. Malik ◽  
Nadeem Abbas
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Differential Equations ◽  
Surface Temperature ◽  
Ordinary Differential Equations ◽  
Nonlinear Partial Differential Equations ◽  
Three Dimensional ◽  
Nonlinear Ordinary Differential Equations ◽  
Exponential Order ◽  
Riga Plate

In this article, we deal with prescribed exponential surface temperature and prescribed exponential heat flux due to micropolar fluids flow on a Riga plate. The flow is induced through an exponentially stretching surface within the time-dependent thermal conductivity. Analysis is performed inside the heat transfer. In our study, two cases are discussed here, namely prescribed exponential order surface temperature (PEST) and prescribed exponential order heat flux (PEHF). The governing systems of the nonlinear partial differential equations are converted into nonlinear ordinary differential equations using appropriate similarity transformations and boundary layer approach. The reduced systems of nonlinear ordinary differential equations are solved numerically with the help of bvp4c. The significant results are shown in tables and graphs. The variation due to modified Hartman number M is observed in θ (PEST) and [Formula: see text] (PEHF). θ and [Formula: see text] are also reduced for higher values of the radiation parameter Tr. Obtained results are compared with results from the literature.

scholarly journals Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5254
Author(s):  
Shizhong Zhang ◽  
Qiu Wang ◽  
Jinping Li ◽  
Xiaoyuan Zhang ◽  
Hong Chen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Temperature ◽  
Thermal Effusivity ◽  
Fast Response ◽  
Test Time ◽  
Physical Parameters ◽  
Fourier Number ◽  
High Enthalpy ◽  
Long Duration

Coaxial thermocouples have the advantages of fast response and good durability. They are widely used for heat transfer measurements in transient facilities, and researchers have also considered their use for long-duration heat transfer measurements. However, the model thickness, transverse heat transfer, and changes in the physical parameters of the materials with increasing temperature influence the accuracy of heat transfer measurements. A numerical analysis of coaxial thermocouples is conducted to determine the above influences on the measurement deviation. The minimum deviation is obtained if the thermal effusivity of chromel that changes with the surface temperature is used to derive the heat flux from the surface temperature. The deviation of the heat flux is less than 5.5% when the Fourier number is smaller than 0.255 and 10% when the Fourier number is smaller than 0.520. The results provide guidance for the design of test models and coaxial thermocouples in long-duration heat transfer measurements. The numerical calculation results are verified by a laser radiation heating experiment, and heat transfer measurements using coaxial thermocouples in an arc tunnel with a test time of several seconds are performed.

Effects of Diesel / Water Emulsion on Heat Flow and Thermal Loading in a Precombustion Chamber Diesel Engine

2001 ◽  
Author(s):  
M. Y. E. Selim ◽  
S. M. S. Elfeky
Keyword(s):  
Heat Flux ◽  
Diesel Engine ◽  
Cylinder Head ◽  
Thermal Loading ◽  
Great Influence ◽  
Metal Temperature ◽  
Water Emulsion ◽  
Precombustion Chamber ◽  
Flux Measurements ◽  
Oil Fuel

Abstract An experimental investigation has been carried out to study the effects of using water / diesel emulsion fuel in an indirect injection diesel engine on the heat flux crossing liner and cylinder head, thermal loading and metal temperature distribution. A single cylinder precombustion chamber diesel engine has been used in the present work. The engine was instrumented for performance, metal temperature and heat flux measurements. The pure gas oil fuel and different ratios of water / diesel emulsion were used and their effects on the heat flux level and the injector tip temperature are studied. Two correlation were found for the heat flux crossing the liner and the cylinder head at various water / diesel emulsion ratios, fuelling rate and thermocouple probe locations. It was found that the addition of water to diesel fuel, to control the nitrogen oxides emissions, has great influence on reducing die heat flux, the metal temperatures and thermal loading of combustion chamber components.

Instantaneous Local Heat Flux Measurements in a Small Utility Engine

2009 ◽  
Author(s):  
Terry Hendricks ◽  
Jaal Ghandhi ◽  
John Brossman
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Numerical Model ◽  
Surface Temperature ◽  
Heat Transfer Rate ◽  
Surface Heat Flux ◽  
Transfer Rate ◽  
Surface Heat ◽  
High Load ◽  
Flux Measurements

Heat flux measurements were performed in an air-cooled utility engine using a fast-response coaxial-type surface thermocouple. The surface heat flux was calculated using both analytical and numerical models. The heat flux was found to be a strong function of engine load. The peak heat flux and initial heat flux rise rate increase with engine load. The measured heat flux data were used to estimate a global heat transfer rate, and this was compared with the heat transfer rate calculated by a single-zone heat release analysis. The measured values of heat transfer were higher than the calculated values largely because of the lack of spatial averaging. The high load data showed an unexplainable negative heat flux during the expansion stroke while the gas temperature was still high. A 1D and 2D finite difference numerical model utilizing an adaptive timestep Crank-Nicholson (CN) integration routine was developed to investigate the surface temperature measurement. Applying the measured surface temperature profile to the 1D model, the resultant surface heat flux showed excellent agreement with the analytical inversion solution and captured the reversal of the energy flow back into the cylinder during the expansion stroke. The 2D numerical model was developed to observe transient lateral conduction effects within the probe and incorporated the various materials used in the construction and assembly of the heat flux sensor. The resulting average heat flux profile for the test case is shown to be slightly higher in peak and longer in duration when compared with the results from the 1D analytical inversion, and this is attributed to contributions from the high thermal diffusivity constituents in the sensor. Furthermore, the negative heat flux at high load was not eliminated suggesting that factors other than lateral conduction may be affecting the measurement accuracy.

scholarly journals The Dynamics of the Antarctic Ice Sheet

1989 ◽  
Vol 12 ◽  
pp. 16-22 ◽  
Author(s):  
W.F. Budd ◽  
D. Jenssen
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Accumulation Rate ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Surface Velocity ◽  
Geothermal Heat ◽  
Antarctic Ice Sheet ◽  
The Past ◽  
The Antarctic

A three-dimensional dynamic, thermodynamic ice-sheet model has been developed to simulate the past, present, and future behaviour of the Antarctic ice sheet. The present ice velocities depend on the deep ice temperatures which in turn depend on the past changes of the ice sheet, including surface temperature, accumulation rate, and ice thickness. The basal temperatures are also strongly dependent on the geothermal heat flux. The model has therefore been used to study the effect on the basal temperatures, of changes to the geothermal heat flux, as well as the past changes of surface temperature and accumulation rate based on results obtained from the Vostok deep ice core. The model is also used to compute the distribution of surface velocity required to balance the present accumulation rate and the dynamics velocity based on the stress, temperature, and flow properties of ice, for the internal deformation, plus a component due to ice sliding. These velocities are compared to observed surface velocities in East Antarctica to assess the state of balance and the performance of the dynamics formulation.

Transient Heat Flux Measurements in a Divided-Chamber Diesel Engine

1985 ◽  
Vol 107 (2) ◽  
pp. 439-444 ◽  
Author(s):  
A. C. Alkidas ◽  
R. M. Cole
Keyword(s):  
Heat Flux ◽  
Diesel Engine ◽  
Fluid Motion ◽  
Local Heat ◽  
Relative Increase ◽  
Heat Fluxes ◽  
Main Chamber ◽  
Peak Heat Flux ◽  
Flux Measurements ◽  
Local Heat Flux

Transient surface heat flux measurements were performed at several locations on the cylinder head of a divided-chamber diesel engine. The local heat flux histories were found to be significantly different. These differences are attributed to the spatial nonuniformity of the fluid motion and combustion. Both local time-averaged and local peak heat fluxes decreased with decreasing speed and load. Retarding the combustion timing beyond TDC decreased the peak heat flux in the antechamber but increased the peak heat flux in the main chamber. This is attributed to the relative increase in the portion of fuel that burns in the main chamber with retarded combustion timing.

On Heat Transfer Measurements in Diesel Engines Using Fast-Response Coaxial Thermocouples

1989 ◽  
Vol 111 (3) ◽  
pp. 458-465 ◽  
Author(s):  
D. N. Assanis ◽  
E. Badillo
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Diesel Engines ◽  
Fast Response ◽  
Rate Of Change ◽  
Thin Film Thickness ◽  
Flux Profile ◽  
Surface Thermocouple ◽  
Engine Components ◽  
Thermocouple Junction

Finite element models of fast-response CO-AX thermocouples typically used for heat transfer measurements in diesel engines have been developed. Due to the small differences in thermal properties between the thermoelements and the iron engine components, CO-AX thermocouples are capable of measuring transient temperatures of iron components within an accuracy of 98 percent. However, these relatively small errors in temperature measurement result in as high as 25 percent errors in peak surface heat flux calculations. This implies that heat flux results depend not only on the temperature of the surface thermocouple junction, but are also sensitive to its time rate of change. Increasing the thin film thickness can significantly alter the heat flux profile deduced from surface junction temperatures.

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