| Author | Murakami, Edgar Gumban |
| Call Number | AIT Thesis no.AE-80-09 |
| Subject(s) | Coconut--Thermal properties
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The specific heat, thermal conductivity and thermal diffusivity of shredded coconut were determined experimentally using several methods. The variables -were moisture content, sample temperature and bulk density. Other physical properties of the sample used like size distribution and
specific gravity were also evaluated. The specific gravity of coconut was constant at moisture content levels 15-48 percent. The average value was 1.018 with 0.025 standard
deviation. The size distribution of the samples used at 2.4 percent
moisture content showed that 86.64 percent were in the range of 0,6 - 1.7 mm. The specific heat of shredded coconut using the method of mixtures ranged from 0.44 - 0.83 cal/g - 0c. It was found to be a linear function
of both moisture content and temperature of the sample.
Thermal conductivity was determined by the transient method. The steady-state method was tried in samples with 1.0 percent moisture content. The thermal conductivity values of shredded coconut using the probe method
were in the range of 0.09 - 0.22 W/m - 0c. Thermal conductivity was not influenced by power input. It was a linear function of moisture content, temperature and bulk density. However, at moisture content levels of 2.4
and 15 percent, the effect of temperature on the value of thermal conductivity diminished. The steady-state method results showed that thermal
conductivity values were not influenced by the mean temperature of the sample. This finding was consistent with the results of the probe method 0 test. At mean temperature range 33.82 - 54.37 C, the steady-state method yielded thermal conductivity values in the range of 0.08 - 0.13 W/m - 0c. The average value was 0.11 W/m - 0 c with 0 .02 7 W/m - 0c standard deviation. Comparatively, at similar conditions the predicted thermal conductivity values in probe method test were in the range of 0.09 - 0.109 W/m - 0c and the average value was 0.097 W/m - 0c with 0.0074 W/m - 0 c standard deviation. Though this value was only 13.4 percent lower than the one found ยท by the steady-state method, it was not conclusive since the steady-state tests were besetted by critical problems like moisture migration and fluctuation of the water flow rate, In the thermal diffusivity determination, the modified probe method and Fourier's test were used. Thermal diffusivity was also computed from
specific heat, bulk density and thermal conductivity values. The probe method results showed that thermal diffusivity was a polynomial function of the second order of moisture content. It was unaffected by bulk density. The thermal diffusivity of shredded coconut by the probe method were in the
uH) range of 0.0008 - 0.0012 cm2 /s. The results of Fourier's test were inconclusive. Though thermal diffusivity was calculated from equations which
assumed it constant -with temperature ratio and time, test results showed that thermal diffusivity values were decreasing with decrease in temperature ratio. However, the change in the values of thermal diffusivity was also decreasing such that at the lower temperature ratios, they were fairly constant. Though -without any theoretical basis, thermal diffusivity was averaged in the temperature ratio range of 0.3 - 0.7 and for comparison, also at 0.3 - 0.5. At the temperature ratio range of 0.3 - 0.7, the average thermal diffusivity per test ranged from 0.0013 - 0.0036 cm2/s and at the
temperature ratio range of 0.3 - 0.5, it ranged from 0.0011 to 0.0023 cm /s. The computed values of thermal diffusivity were relatively insensitive to
moisture content but varied slightly with temperature. It decreased at increasing temperature. The commuted thermal diffusivity values were in
the range of 0.0008 - 0.00104 cm /s. They were lower than those determined by either the probe method or the Fourier's test. |
| Year | 1980 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Jindal, Vinod Kumar
|
| Examination Committee(s) | Singh, Gajendra ;Nguyen, Cong Thanh
|
| Scholarship Donor(s) | Keidanren, Japan |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1980 |