Heat Loss Mechanisms Research Articles

PSII-4 Changes in body temperature of lot-fed Bos taurus and Bos indicus steers during a heat wave

Abstract Body temperature (BT) is a reliable method for evaluating the thermal status of cattle. The objective of this study was to evaluate the regulation of BT in B. indicus and B. taurus steers during a heat wave event. Thirty-five steers (466.30±10.2kg) of mixed genotypes (B. taurus, n = 18; B. indicus, n = 17) were used in a larger 100-d study. Cattle were housed in six un-shaded pens at a commercial feedlot. Body temperature data for this were obtained at 1 h intervals over a 3-d heat wave event using in situ abdominal data loggers. Data were analysed using a repeated measures model, using residual maximum likelihood estimation. The model included genotype (B. taurus; B. indicus) and animal ID as random effects and hour as a fixed effect. Mean maximum BT occurred at 1500 h for B. taurus (40.52±0.03ºC) and 0400 h for B. indicus (40.48±0.31ºC). The BT of B. indicus decreased between 0400 h and 0700 h, and then increased to 1100 h (+0.10±0.01ºC/h), before decreasing again. The BT of B. taurus decreased between 0500 h and 0600 h, and then slowly increased (+0.04±0.01ºC/h) to 1500 h. Mean minimum BT occurred at 2100 h for B. taurus (40.12±0.11ºC) and 0700 h for B. indicus (40.00±0.22ºC). B. taurus maintained lower BT (40.21±0.05ºC) between 1900 h and 2200 h compared to B. indicus (40.27±0.05ºC) which may be due to disrupted heat loss mechanisms during the day, highlighting the importance of night time cooling. In response to increasing heat load, BT in B. taurus had slower increases but retained heat for longer, whilst B. indicus BT responded by a series of rapid increases and decreases. Developing an understanding of the differences in BT regulation in B. indicus and B. taurus will allow for more effective heat load management strategies during heat waves to be established.

147 Changes in body temperature of lot-fed Bos taurus and Bos indicus steers during a heat wave

Abstract Body temperature (BT) is a reliable method for evaluating the thermal status of cattle. The objective of this study was to evaluate the regulation of BT in B. indicus and B. taurus steers during a heat wave event. Thirty-five steers (466.30±10.2kg) of mixed genotypes (B. taurus, n = 18; B. indicus, n = 17) were used in a larger 100-d study. Cattle were housed in six un-shaded pens at a commercial feedlot. Body temperature data for this were obtained at 1 h intervals over a 3-d heat wave event using in situ abdominal data loggers. Data were analysed using a repeated measures model, using residual maximum likelihood estimation. The model included genotype (B. taurus; B. indicus) and animal ID as random effects and hour as a fixed effect. Mean maximum BT occurred at 1500 h for B. taurus (40.52±0.03ºC) and 0400 h for B. indicus (40.48±0.31ºC). The BT of B. indicus decreased between 0400 h and 0700 h, and then increased to 1100 h (+0.10±0.01ºC/h), before decreasing again. The BT of B. taurus decreased between 0500 h and 0600 h, and then slowly increased (+0.04±0.01ºC/h) to 1500 h. Mean minimum BT occurred at 2100 h for B. taurus (40.12±0.11ºC) and 0700 h for B. indicus (40.00±0.22ºC). B. taurus maintained lower BT (40.21±0.05ºC) between 1900 h and 2200 h compared to B. indicus (40.27±0.05ºC) which may be due to disrupted heat loss mechanisms during the day, highlighting the importance of night time cooling. In response to increasing heat load, BT in B. taurus had slower increases but retained heat for longer, whilst B. indicus BT responded by a series of rapid increases and decreases. Developing an understanding of the differences in BT regulation in B. indicus and B. taurus will allow for more effective heat load management strategies during heat waves to be established.

Thermoregulatory and cardiovasculareffects of capsaicin application on human skin during dynamic exercise to temperate and warm conditions.

Thermoregulatory and cardiovascular responses during cycling in temperate and warm environments without and with application of capsaicin on the skin were investigated. We hypothesized that regardless of environmental temperature, capsaicin application would activate heat loss mechanisms attenuating exercise‐induced rectal temperature (Tre) and blood pressure increase. Eight males cycled at 55% of their maximal aerobic power so long as to reach 38.2°C Tre at 20.8 ± 1.0°C and at 30.6 ± 1.1°C ambient temperatures twice: without (NCA) and with (CA) application of capsaicin patches (12 × 18 cm, 4.8 mg). Patches were applied on pectoralis major, trapezius and vastus lateralis muscles. Thermoregulatory (Tre, proximal‐distal skin temperature gradient, sweating rate), cardiovascular variables and oxygen uptake were continuously recorded. In both ambient conditions, during the first 14 min of exercise, the local vasoconstrictive tone as a function of the relative change in Tre was lower in CA than NCA (p < .05, d = 0.84–1.15). Further, sweating rate was higher and occurred at a lower Tre increase in CA compared to NCA (p = .03, d = 0.6) resulting in extended time to reach 38.2°C Tre (p = .03, d = 0.9). Moreover, oxygen consumption was higher in CA than in NCA (p < .001, d = 0.8). Mean arterial pressure was lower during cycling in warm compared to temperate environment, but was unaffected by capsaicin. We conclude that activation of thermal sensors by capsaicin results in lower Tre rise during exercise, which is mediated through greater skin vasodilation along with higher rate and earlier onset of sweating. Nonetheless, capsaicin application has no extra effect on exercise cardiovascular responses.

Experimental and simulated performance of hot mirror coatings in a parabolic trough receiver

Thermal radiation is the dominant heat loss mechanism for receiver units on a parabolic solar collector plant at high temperatures. Reduction of these losses is traditionally achieved through the use of an optically selective coating on the absorber pipe, which absorbs visible light well but emits poorly in the IR region. Another possibility is the use of a hot mirror coating on the glass cover of the receiver, which reflects thermal radiation back onto the absorber pipe for reabsorption. In this paper, novel experimental results of a receiver unit operating with a hot mirror coating are presented, and the results between a developed model and a simulation are compared. It is seen that the correspondence is encouragingly close (Chi-squared test p-values between 0.995 and 0.80), where the simulation underestimates the experimental performance. Further, simulations to investigate the performance of various candidates for hot mirror coating (ITO, Gold, and Silver) in a Solar trough receiver are presented, where it is seen that the hot mirror coating has access to higher temperature regions (above 700 K). Lastly, optical parameter variation effects were simulated, related to overall plant efficiency and compared to existing selective coatings.

Retrofitting suspended timber ground-floors; comparing aggregated and disaggregated evaluation methods

ABSTRACT It is estimated that around 80% of UK dwellings have uninsulated ground floors, representing a significant heat loss mechanism in these buildings. In this research, an aggregated assessment of dwelling heat loss was made using the electric coheating test before and after a ground floor retrofit took place. Heat loss was reduced by 24% (43 ± 18 W/K) indicating that suspended timber ground floor retrofits could improve thermal comfort for occupants and contribute to government domestic energy efficiency policy targets. The findings indicate that disaggregated evaluation methods, such as spot heat flux density measurements, may overestimate the benefits of fabric retrofits. Aggregate methods may therefore be more appropriate tools with which to evaluate retrofits. The U-value improvement resulting from the suspended timber ground floor insulation retrofit, derived via aggregate measurement, was 0.55 W/m²K. Disaggregated spot heat flux density measurements indicated the improvement was 0.89 W/m2K. This research also indicates that Energy Performance Certificates, are unlikely to provide a reliable estimate of energy savings, because they rely on default assumptions for fabric U-Values and ventilation rates. This has implications for policy evaluations as well as householders, who may be excluded from financial support for retrofits.

Thermal Boundaries in Cone Calorimetry Testing

Bench-scale cone calorimetry is often used to evaluate the fire performance of intumescent-type coatings. During the tests, the coating geometry inflates. These thick, block-shaped specimens expose their perimeter side surfaces to both the heat source and the surroundings, unlike the typical thin, plate-shaped samples used in flammability tests. We assessed the thermal boundaries of block-shaped specimens using plain steel solids with several thicknesses. The heat transmitted through the exposed boundaries in convection and radiation modes was determined by four sub-defining functions: non-linear irradiance, convective loss, and radiant absorption into and radiant emission from solids. The individual functions were methodically derived and integrated into numerical calculations. The predictions were verified by physical measurements of the metals under different heating conditions. The results demonstrate that (1) considering absorptivity, being differentiated from emissivity, led to accurate predictions of time-temperature relationships for all stages from transient, through steady, and to cooling states; (2) the determined values for the geometric view factor and the fluid dynamic coefficient of convection can be generalized for engineering applications; (3) the proposed process provides a practical solution for the determination of optical radiative properties (absorptivity and emissivity) for use in engineering; and (4) the heat transmitted through the side surfaces of block specimens should be included in energy balance, particularly in the quantification of a heat loss mechanism. This paper outlines a comprehensive heat transfer model for cone calorimetry testing, providing insights into the mechanism of complex heat transmission generated on the test samples and quantifying their individual contributions.

Experimental study of methane-oxygen premixed flame characteristics in non-adiabatic micro-reactors

In this paper, the effects of Reynolds number, geometrical parameters, and equivalence ratio on methane-oxygen premixed flame dynamics in non-adiabatic micro-reactors were investigated experimentally. The results showed that decreasing the inner diameter of the reactor could significantly influence flame operational regimes and propagation speed in the reactors in terms of suppressing hydrodynamic instabilities and compatibility with theory. In addition, the results showed that increasing the Reynolds number could shift the location of the maximum flame propagation speed in the reactors towards more fuel-lean mixtures. Therefore, it was considered that fuel-rich flames were more stable than fuel-lean ones. Moreover, two mechanisms of heat loss and flame instabilities were found to control flame propagation speed in small-scale reactors. In this regard, unlike the effect of heat loss mechanism on flame propagation speed, the instabilities on the flame surface and the consequent flame surface stretching could lead to a significantly higher flame propagation speed in the reactor than the free propagation flame speed. Meanwhile, it was shown that most established flames in reactors with 1 mm inner diameter were symmetric and more controllable. However, the flame shape in reactors with 2 mm inner diameter could be asymmetric under certain conditions.

Stefan flow induced natural convection suppression on high-flux evaporators

High-flux evaporators are important for various fundamental research and industrial applications. Understanding the heat loss mechanisms, especially the contribution of natural convection during evaporation is thus a ubiquitous process to predict and optimize the performance of evaporators. However, a comprehensive analysis on natural convection heat transfer, where the vertical Stefan flow due to evaporation couples with buoyancy driven convective flow has not been carefully considered. In this work, we developed a theoretical framework to elucidate the effect of Stefan flow on natural convection during evaporation. This theory incorporates the vertical Stefan flow into the conventional boundary layer theory. We found that a significant suppression of natural convection can be induced by a weak Stefan flow owing to the increase of boundary layer thickness. To understand this phenomenon, we discuss the governing mechanisms at different Stefan flow regimes. We provide a theoretical correlation to the overall heat transfer which includes both effects of the Stefan flow velocity and the buoyancy force. We finally predict the effect of natural convection on an evaporator at different operating temperatures. The heat loss from natural convection no longer monotonically increases with the superheat temperature due to the effect of Stefan flow suppression. As a result, there is an approximately 40% overestimation of the natural convection contribution at saturation temperature using conventional theory. This work improves the fundamental understanding of the natural convection during evaporation and can help guide future high-performance evaporator designs.

AGE-RELATED FEATURES OF MORPHOFUNCTIONAL STATUS AND TEMPERATURE HOMEOSTASIS IN HIGHLY SKILLED FOOTBALL PLAYERS

Aim. The article deals with establishing the features of morphofunctional characteristics and temperature balance in highly skilled football players aged 17–21. Materials and methods. Within the framework of the study, the following methods have been used: questioning; anthropometry; dynamometry; spirometry; echocardiography; electrocardiography at rest and before physical activities; functional measurements and tests; assessment of the thermal status. 18 football players participated in the study (the team from the Russian State University of Physical Education, Sport, Youth and Tourism). Results. We revealed significant age-related differences in the integral indicator of the life index. At the first stage of maturity, we registered an increase of the life index, which indicates the improvement of the functional reserves of the respiratory system under regular physical loads connected with playing football. We studied the indicators of physical performance and aerobic capacities in the football players of different age groups. We revealed age-related differences in physical performance during a two-stage PWC170 test with a submaximal physical load of 70–80 % of VO2 max. We also revealed age-related differences in the indicators of external respiration in highly skilled football players. The assessment of the thermal status was conducted with temperature measurement in 5 areas: the forehead, chest, abdomen, thigh, and back (CorTemp® body temperature recorder). The most pronounced diffe­rences in temperature were registered in athletes with various results in the PWC170 test. Conclusion. The data obtained indicate an adaptive increase of average-weighted skin temperature during the first load and active involvement of such a mechanism of heat loss like sweat evaporation during the second load. Two types of temperature curves are distinguished in accordance with temperature changes: the inert type and plastic type. The plastic type is characterized by a decrease of average skin temperature below the temperature at rest after a pause before the second load. The inert type is characterized by a smooth increase in skin temperature during the first load. A further increase was two times lower than that of the first load.

Resolution, energy and time dependency on layer scaling in finite element modelling of laser beam powder bed fusion additive manufacturing

The Laser Beam Powder Bed Fusion (PBF-LB) category of Additive Manufacturing (AM) is currently receiving much attention for computational process modelling. Major challenges exist in how to reconcile resolution, energy and time in a real build, with the practical limitations of resolution (layer height and mesh resolution), energy (heat format and magnitude) and time (heating and cooling step times) in the computational space. A novel thermomechanical PBF-LB process model including an efficient powder-interface heat loss mechanism was developed. The effect of variations in layer height (layer scaling), energy and time on the temperature and stress evolution was investigated. The influence of heating step time and cooling step time was characterised and the recommended ratio of element size to layer scaling was presented, based on a macroscale 2D model. The layer scaling method was effective when scaling up to 4 times the layer thickness and appropriately also scaling the cooling step time. This research provides guidelines and a framework for layer scaling for finite element modelling of the PBF-LB process.

A decentralized biomass torrefaction reactor concept. Part II: Mathematical model and scaling law

In Part I of the study, we proposed a simplified biomass torrefaction moving bed reactor design capable of decentralized, small-scale, and mobile deployment operated under an oxygen-lean condition. We built and validated a laboratory-scale test reactor. In the present study, we develop a mathematical description of the reactor and show that it produces reasonable fit to our experimental data. Contrary to many existing biomass gasifier studies, we demonstrate that at the small test-reactor scale, heat loss mechanism through the side wall is significant and cannot be ignored in the modeling. We further demonstrated that at the small test-reactor scale, the rapid axial thermal conduction plays a role in the heat transfer within the moving bed. Furthermore, by interrogating the scaling behaviors of the reactor, we show that as we scale up our current laboratory-scale reactor, at the same torrefaction severity, the mass yield of the torrefied biomass is predicted to increase by 10–20%, due to the decrease in relative heat losses at a larger scale. This study, therefore, seeks to understand and quantify some of the limitations of testing a scaled-down reactor prototype. The understanding gained in this study can both inform scaling laws for at-scale reactor designs, as well as point out areas of future work in order to develop a higher-fidelity description.

A Finite Element Study of Thermo-Mechanical Fields and Their Relation to Friction Conditions in Al1050 Ring Compression Tests

The most accepted method for determining friction conditions in metal forming is the ring compression test (RCT). At high temperatures, extraction of the friction coefficient, μ, commonly requires numerical analysis due to the coupling between the mechanical and thermal fields. In the current study, compression tests of cylindrical specimens and RCT experiments were conducted on commercially pure aluminium (Al1050) at several temperatures, loading rates, and lubrication conditions. The experiments were used in conjunction with a coupled thermo-mechanical finite element analysis to study the dependence of the friction coefficient on those parameters. It is demonstrated that due to the coupling between friction conditions and material flow stress, both μ and flow stress data should be determined from the cylinder and ring specimens simultaneously and not subsequently. The computed friction conditions are validated using a novel method based on identification of the plastic flow neutral radius. It is shown that, due to heat loss mechanisms, the experimental system preparation stage must be incorporated in the computational analysis. The study also addresses the limitation of the RCT in the presence of high friction conditions. The computational models are finally used to examine the thermo-mechanical fields, which develop during the different processes, with an emphasis on the effect of friction conditions, which were then correlated to the resulting microstructure in the RCTs.

A 2D model for low-pressure hollow cathode arc discharges in argon

A 2D fluid model is presented in this paper to study axisymmetric hollow cathode arc discharge, in which the equations of particle and particle energy transport, neutral gas flow and heating, and cathode thermal balance are included. This model can overcome the deficiency of other non-self-consistent models, where some boundary conditions must be predefined. In this work, the spatial variations of the electron density and temperature, gas temperature, and cathode wall temperature were investigated under various radii, thicknesses and surface emissivities of the hollow cathode. It is found that the cathode wall temperature was far below the measured wall temperature if the model neglected the contribution of the Joule heating of ions, while the calculated value was in good agreement with the measured one if the model took into account the contribution of the Joule heating of ions. This finding indicates that the Joule heating of ions played an important role and should not be neglected in the modeling of low-pressure hollow cathode discharges. The results also show that the domain and location of the plasma column inside the cathode tube were dependent on the pressure, pressure gradient, and gas temperature, and that the surface thermal radiation was a primary heat loss mechanism on the cathode. In addition, this paper also analyzed the formation of the cathode sheath and evaluated the sheath thickness.

Performance of evacuated flat plate solar thermal collectors

Heat losses from a flat panel solar collector can be significantly reduced by lowering the internal pressure to <0.5 Pa. Compared with conventional collectors, the resulting increase in efficiency is predicted to give a significant gain in annual heat output in the context of a temperate climate with low median irradiance.Two experimental collectors were built and tested to investigate theoretical aspects of evacuated flat plates and develop appropriate technological solutions. One had a metal tray to the rear, the other used two sheets of glass. An array of pillars supports the glass against atmospheric pressure. The experimental procedure was designed to minimise measurement uncertainty. Testing under a solar simulator, with and without a vacuum, showed a sudden drop in heat loss as the pressure was reduced below 0.5 Pa. When evacuated the heat loss coefficient fell from 7.43 to 3.65 W/m2 K and the efficiency at a nominal test condition of ΔT = 60 °C, G = 1000 W/m2 increased from 36% to 56%. Heat losses from absorber to glass were within 9% of the predicted level. This demonstrates that the heat loss mechanism is well understood.

Effects of seasonal fluctuations of surface heat flux and wind stress on mixing and vertical diffusivity of water column in deep lakes

Abstract Accurate vertical diffusivity estimates at different stratification conditions are essential to correctly model vertical mixing of discharges into lakes. This study presents calculated variations in vertical mixing at different depths in Boulder Basin, Lake Mead, a deep reservoir over a four-year period using hourly weather data and 6-hourly measured temperature, conductivity, and DO profiles. Turbulent Kinetic Energy (TKE) and mixing intensities within Boulder Basin, calculated based on surface heat flux and wind speed were compared to water column stability and diffusivity over the study period. Analysis of surface heat fluxes showed that evaporation and longwave radiation were the main heat loss mechanisms in summer and winter, respectively. The lake showed strong summer stratification with stability numbers N2 > 10−4 s−2, followed by increased water column instability during fall and eventually winter overturn, resulting in gradient Richardson numbers

Predicting recovery from exertional heat strain in military working dogs

A two-compartment (core, skin) rational Canine Thermal Model (CTM) of thermal-physiological responses was developed to predict the core temperature (Tc) of a military working dog (MWD) during recovery from exertional heat stress. Heat storage is represented as the balance among heat loss mechanisms, heat gain from the environment, and heat production from metabolism. Inputs to the CTM include environmental conditions (ambient temperature, relative humidity, solar radiation and wind speed), physical characteristics of the dog (weight, length), and metabolic rate. The CTM was validated against Tc of 16 MWDs measured in a previous study, where training was conducted in October (24 °C, 52% RH), March (14 °C, 74% RH), and August (28 °C, 64% RH). Measured and CTM-simulated Tc were compared at 5, 10, 15, 30 and 60 min post-exercise. The CTM was considered acceptable if it was within 0.5 °C of measured Tc for 80% of cases. This occurred in 92% of 37 cases after 30 min recovery, and 86% of 29 cases after 60 min. The mean difference between CTM-simulated and measured Tc was − 0.01 °C at 30 min recovery, with 2 of 37 cases falling outside the range of two standard deviations (Bland Altman comparison). After 60 min recovery the difference was 0.05 °C, with 4 of 29 cases outside the range of acceptance. The root mean squared deviation between CTM-simulated and measured Tc for all time points was 0.3 °C ± 0.3 °C. For comparison, the mean ± standard deviation of resting Tc was 38.2 °C ± 0.3 °C and at peak Tc was 39.4 °C ± 0.7 °C. For this population, the CTM is a valid method for simulating recovery from exertional heat stress. It can be used to develop work / rest cycles during activity in hot environments, and to compare rates of recovery across different environmental conditions.

Timings of early crustal activity in southern highlands of Mars: Periods of crustal stretching and shortening

Extensional and compressional structures are globally abundant on Mars. Distribution of these structures and their ages constrain the crustal stress state and tectonic evolution of the planet. Here in this paper, we report on our investigation over the distribution of the tectonic structures and timings of the associated stress fields from the Noachis-Sabaea region. Thereafter, we hypothesize possible origins in relation to the internal/external processes through detailed morphostructural mapping. In doing so, we have extracted the absolute model ages of these linear tectonic structures using crater size-frequency distribution measurements, buffered crater counting in particular. The estimated ages indicate that the tectonic structures are younger than the mega impacts events (especially Hellas) and instead they reveal two dominant phases of interior dynamics prevailing on the southern highlands, firstly the extensional phase terminating around 3.8 Ga forming grabens and then compressional phase around 3.5–3.6 Ga producing wrinkle ridges and lobate scarps. These derived absolute model ages of the grabens exhibit the age ca. 100 Ma younger than the previously documented end of the global extensional phase. The following compressional activity corresponds to the peak of global contraction period in Early Hesperian. Therefore, we conclude that the planet wide heat loss mechanism, involving crustal stretching coupled with gravitationally driven relaxation (i.e., lithospheric mobility) resulted in the extensional structures around Late Noachian (around 3.8 Ga). Lately cooling related global contraction generated compressional stress ensuing shortening of the upper crust of the southern highlands at the Early Hesperian period (around 3.5–3.6 Ga).

Heat Transfer Study of the Hencken Burner Flame

The Hencken burner flame is often used in combustion laser diagnostics as a calibration flame because of its near adiabatic condition. For a fast burning H2 flame, it can tolerate high flow rate and the flame is indeed near adiabatic; however, for a slow burning CH4 flame, the flow rate is not always high enough to maintain near adiabatic conditions. The heat transfer of the H2 and CH4 Hencken burner flames are studied numerically and experimentally. Three heat loss mechanisms are analyzed: the burner surface radiation, the hot gas radiation, and the convection heat transfer between the main flow and the co-flow. The surface radiation produces negligible temperature drop while the gas radiation and the convection heat loss contribute significant temperature drop. Reducing the co-flow rate can decrease the convection heat loss slightly. The temperature drop caused by the heat loss is inversely proportional to the main flow rate. Increasing the burner size and running the flame premixed mode can increase the flow rate and reduce the temperature deviation from the adiabatic equilibrium value. Based on the heat loss and temperature drop analysis, suggestions are given to maintain the flame at near adiabatic conditions.

The study on the heater usage for better energy efficiency of domestic convection oven

In this study, the heater usage algorithm has been studied for cooking process in a domestic oven. For the analysis, numerical simulation and experimental study have been performed, focusing on heat distribution and heat loss mechanism. Better fidelity of baking process model was achieved by incorporating enthalpy jump at the phase change and evaporation-condensation mechanism into the thermal properties of cupcake. The result of heat flux calculation over enclosed walls shows that the back surface has the highest heat flux due to high temperature of convection heating during preheating process. During baking process, the heat flux on the top surface of cupcake on a upper tray was found to be about 1.8 times as that on the lower tray due to radioactive heat flux from grill heater. For an energy saving purpose, the more balanced use of heating units, for instance, more use of grill heater than convection heater, was recommended. The thermal conductivity of insulation material was a more important factor than specific heat on the power consumption during preheating.

Modelling microwave heating of an oil palm mesocarp

An oil palm mill often uses steam in sterilization and fruit detachment processes. Consequently, a large amount of wastewater is produced. To reduce the wastewater, microwave (MW) heating of oil palm fruits has been studied and positive results were reported in open literature. Nevertheless, MW heating of oil palm fruits requires proper control to avoid overheating, which deteriorates the oil quality. MW heating efficiency depends not only on the electromagnetic strength, but also on the complex permittivity of oil palm fruits. This study reports the MW heating model of an oil palm mesocarp. The three-dimensional model solved Maxwell’s Electromagnetic waves equation, diffusion equation of moisture content, and heat conduction equation. The model was validated with mesocarp’s experimental data of moisture content and temperatures. The electromagnetics, moisture, and temperature distributions of the mesocarp were studied. The simulation results showed that the volumeand surface-averaged temperature were similar, thus the surface temperature might be used as a good approximation to the volumetric temperature. Besides, the model also showed that radiation and convection were the main heat loss mechanisms. This validated model can be used for designing a microwave heating reactor for oil palm fruits.