Transient Temperature Response of Variable Flow Heat Exchangers in a Marnoch Heat Engine

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
P. Saneipoor ◽  
G. F. Naterer ◽  
I. Dincer
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Heat Engine ◽  
Heat Transfer Model ◽  
Transient Temperature ◽  
Transfer Model ◽  
Gas Temperature ◽  
Variable Flow ◽  
Flow Heat ◽  
Shell And Tube

Within a Marnoch heat engine (MHE), a water/glycol mixture transfers heat from the heat source into a set of variable flow heat exchangers and removes heat from adjoining cold heat exchangers. The compressed dry air is used as the working medium in this heat engine. The MHE has four shell and tube heat exchangers, which operate transient and variable flow conditions. A new transient heat transfer model is developed to predict this transient behavior of the heat exchangers for different flow regimes and temperatures. The results from the model are validated against experimental results from an MHE prototype. The heat transfer model shows 85% agreement with measured data from the MHE prototype for the individual heat exchangers. This model can be used for similar shell and tube heat exchangers with straight or U-shaped tubes. The heat transfer model predicts the gas temperature on the shell side, when a step change is imposed on the liquid entering the tubes.

scholarly journals Numerical modelling of vertical borehole heat exchangers performance under Lithuanian Quaternary conditions

Baltica ◽  
2019 ◽  
Vol 31 (2) ◽  
pp. 146-153
Author(s):  
Audrius Indriulionis ◽  
Žygimantas Palaitis ◽  
Petras Šinkūnas ◽  
Robert Mokrik
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Groundwater Flow ◽  
Heat Exchangers ◽  
Heat Transfer Model ◽  
Capital City ◽  
Transfer Model ◽  
Practical Tool ◽  
Borehole Heat Exchangers ◽  
Vertical Borehole

The vertical borehole heat exchangers were surrounded by the heterogeneous multilayered geological environment and groundwater flow that affected the performance of borehole plants. In this paper, the field investigation of vertical borehole ground heat exchangers in capital city Vilnius (Visoriai), Lithuania is presented. The numerical heat transfer model considering seven different geological strata was developed using the cylindrical heat sink model for vertical borehole inside by solving the soil mass and heat transfer equations with groundwater flow. The numerical multilayered ground vertical borehole heat transfer model was calculated and validated by in-situ thermal response test data. The numerical model results were also compared with the homogeneous finite difference model expressed by the temperature response functions (well known as “g-functions”). The practical realization of g-functions was designed in the Earth Energy Designer as a practical tool for geoengineers designing the vertical borehole plants. The temperature profiles at borehole wall at different heating times were presented and explored together with relative errors. The numerical model will be used as a practical tool for the Lithuanian Geological Survey under the Ministry of Environment to estimate the underground conditions for the consumption of shallow geothermal energy.

2-D Transient Radiative Heat Transfer Analysis on the Slab in a Walking-Beam-Type Reheating Furnace

2014 ◽  
Vol 610 ◽  
pp. 993-997 ◽  
Author(s):  
Jun Bo Huang ◽  
Jiin Yuh Jang ◽  
Chien Nan Lin ◽  
Chao Hua Wang
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Thermal Radiation ◽  
Transient Heat Conduction ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Gas Temperature ◽  
Reheating Furnace ◽  
Hot Gas ◽  
Beam Type

A two-dimensional mathematical heat transfer model for the prediction of temperature distribution within the slab has been developed by considering the thermal radiation in the walking-beam-type reheating furnace chamber and transient heat conduction in the slab, respectively. The steel slabs are heated up through the preheating, heating, and soaking zones in the furnace. Heat transfer characteristics and temperature uniformity of the slab is investigated by changing hot gas temperature. Comparison with the in-situ experimental data show that the present heat transfer model works well for the prediction of thermal behavior of the slab in the reheating furnace. The skid mark severity decreases with an increase in hot gas temperature. Keywords: Reheating Furnace, Thermal Radiation, Transient heat conduction

A Study on Heat Transfer Model in Wood Particle during the Pyrolysis

2011 ◽  
Vol 704-705 ◽  
pp. 462-467
Author(s):  
Liang Jing Jing ◽  
Rui Li ◽  
Yu Yu Li
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Thermal Behavior ◽  
Thermophysical Properties ◽  
Fast Pyrolysis ◽  
Wood Particle ◽  
Heat Transfer Model ◽  
Transient Temperature ◽  
Transfer Model ◽  
Optimization Of Parameters

Heat transfer in wood particle controls the process of the pyrolysis. This paper makes a 2-D transient heat transfer model in cylindrical to predict the thermal behavior of wood particle in the process of fast pyrolysis. Wood anisotropy and thermophysical properties are considered in this model, as well as the influence of heat reaction on temperature distribution in wood particle. Based on the calculation of transient temperature in wood particle, and analysis of the temperature distribution during the process of wood fast pyrolysis at different time, this paper preliminarily discusses the optimization of parameters in wood particle fast pyrolysis. Keywords: pyrolysis, heat transfer, particle, wood

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