scholarly journals Pemodelan pada Pengeringan Pneumatik Mekanis Tepung Kasava: Hubungan Koefisien Pindah Panas dengan Variabel Pengeringan (Modelling on Mechanical Cassava Flour Pneumatic Drying: Correlation of Heat Transfer Coefficient and Drying Variables)

2016 ◽  
Vol 36 (03) ◽  
pp. 362 ◽  
Author(s):  
Yus Witdarko ◽  
Nursigit Bintoro ◽  
Bandul Suratmo ◽  
Budi Rahardjo
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Dimensional Analysis ◽  
Coefficient Of Determination ◽  
Process Variables ◽  
Drying Process ◽  
Cassava Flour ◽  
Pneumatic Drying ◽  
The Relationship

In the cassava flour pneumatic drying process, mostly heat transfer occurred in convective mode. One of variables which could be used to evaluate the effectiveness of drying processperformance is heat transfer coefficient (h) during drying. The objectives of the research was to formulate a mathematical relationship between h and various pneumatic drying process variables of cassava flour by applying dimensional analysis. In the following research it had been constructed a pneumatic drying machine which was able to be according to the needed data that will be collected. Several parameters related to physical and thermal properties as well as operation of the drying machine were measured and used as the analysis variables was solved using dimensional analysis. Based on the result of the data, it was obtained that the relationship between h and the drying process variables could be expressed as follows  This equation had quite high coefficient of determination, so that it could be used to predict the heat transfer coefficient in pneumatic drying process. Sensitivity analysis indicated that the dimensionless product which had the largest effect on h was   .ABSTRAKPada proses pengeringan tepung kasava secara pneumatik, perpindahan panas terjadi terutama secara konveksi. Salah satu parameter yang digunakan untuk mengevaluasi efektivitas kinerja proses pengeringan tersebut adalah koefisien perpindahan panas (h) yang terjadi selama pengeringan. Tujuan dari penelitian ini adalah untuk menghubungkan secara matematis antara nilai h dengan beberapa variabel proses pengeringan pneumatik tepung kasava dengan menggunakan metode analisis dimensi. Pada penelitian ini telah dikonstruksi suatu mesin pengering pneumatik yang dirancang untuk dapat dilakukan pengaturan-pengaturan sesuai dengan kebutuhan data penelitian yang akan dikumpulkan. Beberapa parameter yang terkait dengan sifat fisik dan sifat thermis bahan serta operasional mesin pengering diukur dan digunakan sebagai variabel-variabel analisis yang diselesaikan dengan metode analisis dimensi. Berdasarkan hasil analisis data diperoleh hubungan antara nilai h dengan variabel-variabel proses pengeringan sebagai berikut    Persamaan tersebut mempunyai nilai koefisien determinasi yang cukup besar, sehingga dapat digunakan untuk memprediksi koefisien perpindahan panas pada pengeringan pneumatic. Hasil uji sensitivitas menunjukkan bahwa dimensionless product yang paling berpengaruh terhadap nilai h adalah    .Kata kunci: Tepung kasava; analisis dimensi; koefisisen perpindahan panas; pneumatic drying

scholarly journals PEMODELAN MATEMATIS HUBUNGAN KADAR AIR TEPUNG DENGAN VARIABEL PROSES PADA PENGERINGAN MEKANIS TEPUNG KASAVA MENGGUNAKAN PNEUMATIC DRYER

2016 ◽  
Vol 36 (01) ◽  
pp. 111 ◽  
Author(s):  
Yus Witdarko ◽  
Nursigit Bintoro ◽  
Bandul Suratmo ◽  
Budi Rahadjo
Keyword(s):  
Moisture Content ◽  
Dimensional Analysis ◽  
Important Variable ◽  
Coefficient Of Determination ◽  
Process Variables ◽  
Drying Process ◽  
Cassava Flour ◽  
Input Capacity ◽  
Pneumatic Drying ◽  
The Relationship

Moisture content of the materials (Ka) is the most important variable in evaluating the performance of drying process, therefore the ability to predict moisture-content of the materials in the drying process is very important. The objective of this research was to formulate a mathematical relationship between various pneumatic drying process variables and the moisturecontent of the materials of cassava flour by applying dimensional analysis. In this research, a pneumatic drying equipment and test edit in wide varieties of treatments, such as the input capacity, drying air temperature, and drying air velocity. Based on the result of data analysis, it was obtained that the relationship between moisture content of the materials and the drying process variables could be expressed as followThis equation had 0,722 coefficient of determination, so that it could be used to predict the moisture content of cassava flour precisely. Sensitivity analysis indicated that the dimensionless product which had the largest effect on Ka was.Keywords: Cassava flour, pneumatic drying, dimensional analysis, moisture content ABSTRAKKadar air bahan (Ka) merupakan variabel yang paling penting dalam mengevaluasi kinerja proses pengeringan bahan, sehingga kemampuan untuk memprediksi Ka dalam proses pengeringan akan menjadi sangat penting. Penelitian ini bertujuan untuk memformulasikan hubungan matematis antara berbagai variabel proses pengeringan secara pneumatik dengan Ka akhir tepung ketela pohon dengan menerapkan analisis dimensi. Pada penelitian ini telah dirancang peralatan pneumatic drying dan dilakukan pengujian dengan berbagai macam variasi perlakuan seperti kapasitas input, temperatur udara pengering, dan kecepatan udara pengering. Berdasarkan hasil analisis data maka diperoleh hubungan antara Ka dengan variabel-variabel proses pengeringan sebagai berikut:Persamaan tersebut mempunyai nilai koefisien determinasi 0,722 sehingga besar kemungkinan untuk dapat digunakansebagai alternatif dalam memprediksi kadar air tepung hasil pengeringan. Hasil uji sensitivitas menunjukkan bahwadimensionless product yang paling berpengaruh terhadap nilai Ka adalah    ்ೠ   .Kata kunci: Tepung kasava, pneumatic drying, analisis dimensi, kadar air

scholarly journals PEMODELAN PROSES PENGERINGAN MEKANIS TEPUNG KASAVA DENGAN MENGGUNAKAN PNEUMATIC DRYER: HUBUNGAN KAPASITAS OUTPUT DENGAN VARIABEL PROSES PENGERINGAN (Modelling on Mechanical Cassava Flour Drying Process by Using Pneumatic Dryer: Correlation of Output Capacity and Drying Process Variables)

2016 ◽  
Vol 36 (02) ◽  
pp. 233
Author(s):  
Yus Witdarko ◽  
Nursigit Bintoro ◽  
Bandul Suratmo ◽  
Budi Rahadjo
Keyword(s):  
Simple Calculation ◽  
Coefficient Of Determination ◽  
Process Variables ◽  
Drying Process ◽  
Mathematical Relationship ◽  
Cassava Flour ◽  
Output Capacity ◽  
Pneumatic Drying ◽  
Process Output

In the drying process, output capacity (Qo) is one of important parameter which should be known because it can beused to evaluate the effectiveness of drying process performance. Theoritically, determination of the output capacityof the drying machine in pneumatic drying is still relatively complex. So, a simple calculation method to predictoutput capacity of the pneumatic drying machine is required. The main objective of this research was to formulatea mathematical relationship between Qo value and various pneumatic drying variables of cassava flour by applyingdimensional analysis. The results showed relationship between Qo value and the drying process variables as follows:This equation has a quite high coefficient of determination, and potentially usable for predicting the output capacity inpneumatic drying. Sensitivity analysis indicated that the dimensionless product which had the largest effect on Qo was ...that reached 11.53%.Keywords: Cassava flour, pneumatic drying, dimensional analysis, output capacity ABSTRAKPada proses pengeringan, kapasitas output (Qo) merupakan salah satu parameter penting yang perlu diketahui.Parameter ini dapat dipakai untuk mengevaluasi efektivitas kinerja proses pengeringan. Pada metode pengeringansecara pneumatik, penentuan kapasitas output mesin pengering secara teoritis, masih relatif komplek. Diperlukan caraperhitungan yang lebih sederhana untuk dapat memprediksi kapasitas output mesin pengering pneumatik. Tujuandari penelitian ini adalah untuk menghubungkan secara matematis antara nilai Qo dengan beberapa variabel prosespengeringan pneumatik tepung kasava dengan menggunakan metode analisis dimensi. Hasil analisis data memberikanhubungan antara nilai Qo dengan variabel-variabel proses pengeringan sebagai berikut:Persamaan tersebut mempunyai nilai koefisien determinasi yang cukup besar, sehingga dapat digunakan untukmemprediksi kapasitas output pada pengeringan pneumatik. Hasil uji sensitivitas menunjukkan bahwa dimensionlessproduct yang paling berpengaruh terhadap nilai Qo adalah ... yang mencapai 11,53%.Kata kunci: Tepung kasava, pneumatic drying, analisis dimensi, kapasitas output

scholarly journals Relationship modelling between moisture content of flour and variables of two-cycle drying process of cassava flourusing pneumatic dryer

2018 ◽  
Vol 73 ◽  
pp. 05014
Author(s):  
Witdarko Yus ◽  
Betaubun Philipus ◽  
Jayadi
Keyword(s):  
Moisture Content ◽  
Process Variable ◽  
Important Variable ◽  
Process Variables ◽  
Drying Process ◽  
Air Velocity ◽  
Cassava Flour ◽  
Input Capacity ◽  
Pneumatic Drying ◽  
The Relationship

Moisturecontent (MC) is the most important variable in evaluating material drying performance, so the ability to predict MC in drying process is really important. This research aims to formulate the mathematic relationship between drying process variable pneumatically and moisture content of cassava flour in drying process 1 and 2 by applying dimensional analysis. In this research, there has been a design of pneumatic drying equipment and test using various treatments such as input capacity, drying air temperature, and drying air velocity. Based on the data analysis, the relationship between MC and drying process variables are as follow: Drying cycle 1: MC = (5,794287E − 22). (ρpr·Dpr3/Qi·θ)1,4085 (Tu/Tbo)-2,2504 (Vu·θ/Dpr)5,863 Drying cycle 2: MC = (2,36831E − 10). (ρprDpr3/Qi·θ)1,059 (Tu/Tbo)-4.808 (Vu·θ/Dpr)3,709 The equations have determination coefficient value 0.85, so it has big possibility to use it as alternative to predict moisture content of dried flour.

The Surface Heat Transfer Coefficient Model of 7075 Al-Alloy Extrusion Product and its Temperature Prediction

2013 ◽  
Vol 749 ◽  
pp. 229-236
Author(s):  
Wen Rong Hou ◽  
Wei Bing Ji ◽  
Zhi Hao Zhang ◽  
Jian Xin Xie
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Surface Heat ◽  
Al Alloy ◽  
Surface Heat Transfer ◽  
7075 Al Alloy ◽  
Surface Heat Transfer Coefficient ◽  
Extrusion Product ◽  
The Relationship

Surface heat transfer coefficient is a key parameter for accurately predicting the extrusion product temperature near the die exit and then achieving isothermal extrusion by speed controlling. Based on the heat transfer characteristics of extrusion product during cooling process, a dynamic loading method of heat transfer boundary conditions was proposed. The surface heat transfer coefficient model of 7075 Al-alloy extrusion product was established using the dynamic loading method and inverse calculation comprehensively. The model indicated the relationship among surface heat transfer coefficient h, surface temperature T and initial temperature T0 as h=1.16T-0.97T0. Its accuracy is high enough for calculating the surface temperature of 7075 Al-alloy extrusion product. According to the model and the experimental data, the relationship between the product and the measured temperatures can be established. It provides an effective way to solve the problem that the extrusion product temperature near the die exit cannot be directly measured.

scholarly journals An Experimental Investigation on the Heat Transfer Coefficient of Oscillating Heat Pipes

2013 ◽  
Vol 732-733 ◽  
pp. 78-82
Author(s):  
Ling Gao ◽  
Wen Guang Geng ◽  
Xiao Xu Ma ◽  
Xiu Li Ma ◽  
Guang Liang Luo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Transfer Coefficient ◽  
Relative Humidity ◽  
Transfer Coefficient ◽  
Convective Heat Transfer Coefficient ◽  
Heat Pipes ◽  
Oscillating Heat Pipe ◽  
Hot Air ◽  
The Relationship

This paper presents an experimental study on total heat transfer coefficient (ht) in oscillating heat pipe heat exchanger hot air flow tunnels, ht plays an important role in the oscillating heat pipes design process. In this paper, ht and the convective heat transfer coefficient (h) was investigated by experimentally and theoretical calculation respectively. From experimental study, the relationship between the ratio of heat transfer coefficient and the relative humidity is obtained. The results show that the ratio of ht to h increases from 5 to 20 as the relative humidity of the hot gas increasing from 19.22% to 60%. According to the experimental data, a matched curve and an empirical equation were presented, which can be described as ht=h(1.87783+0.09631x+0.0032x2).

scholarly journals PEMODELAN PADA PROSES PENGERINGAN MEKANIS TEPUNG KASAVA DENGAN MENGGUNAKAN PNEUMATIC DRYER: HUBUNGAN FINENESS MODULUS DENGAN VARIABEL PROSES PENGERINGAN

2015 ◽  
Vol 35 (04) ◽  
pp. 481 ◽  
Author(s):  
Yus Witdarko ◽  
Nursigit Bintoro ◽  
Bandul Suratmo ◽  
Budi Rahardjo
Keyword(s):  
Dimensional Analysis ◽  
Process Condition ◽  
Average Diameter ◽  
Drying Methods ◽  
Drying Process ◽  
Cassava Flour ◽  
Pneumatic Drying ◽  
Air Dryer ◽  
Fineness Modulus

One of the drying methods, which are applied in the industry of flour production, is that pneumatic drying. A wide variety of the variables that are from both of the characteristics of the dried material and drying process condition greatly affect the quality of drying result. Fineness Modulus (FM) and average diameter of flour are important variables in determining the quality of the flour. The objectives of this research was to formulatea mathematical relationship between various pneumatic drying process variables with the fineness modulus of the materials of cassava flour by applying dimensional analysis. In order to realize this goal, pneumatic drying equipment has been designed and tested with a wide variety of treatments such as the input capacity, drying air velocity, particle’s flour diameter, and temperature of air dryer as well.Keywords: Cassava flour, pneumatic drying, dimensional analysis, fineness modulus ABSTRAKMetode pengeringan yang diterapkan dalam industri pembuatan tepung salah satunya adalah pneumatic drying. Berbagai macam variabel baik dari sifat-sifat bahan yang dikeringkan maupun kondisi proses pengeringan sangat mempengaruhi kualitas hasil pengeringan. Fineness Modulus (FM) dan diameter tepung rata-rata merupakan variabel-variabel yang penting dalam penentuan kualitas dari tepung. Tujuan dari penelitian ini adalah untuk mencari hubungan matematis antara FM dengan variabel-variabel kondisi proses pengeringan pneumatik. Untuk dapat mewujudkan tujuan tersebut telah dirancang peralatan pneumatic drying dan dilakukan pengujian dengan berbagai macam variasi perlakuan seperti kapasitas input, kecepatan udara pengering, diameter partikel tepung, dan temperatur udara pengering.Kata kunci: Tepung ubi kayu, pneumatic drying, analisis dimensi, fineness modulus

Two-Dimensional Analysis of Conduction-Controlled Rewetting With Precursory Cooling

1976 ◽  
Vol 98 (3) ◽  
pp. 407-413 ◽  
Author(s):  
S. S. Dua ◽  
C. L. Tien
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Dimensional Analysis ◽  
Vertical Surface ◽  
Dimensionless Temperature ◽  
Two Dimensional ◽  
Dimensional Solution ◽  
One Dimensional ◽  
The One

This paper presents a two-dimensional analysis of the effect of precursory cooling on conduction-controlled rewetting of a vertical surface, whose initial temperature is higher than the sputtering temperature. Precursory cooling refers to the cooling caused by the droplet-vapor mixture in the region immediately ahead of the wet front, and is described mathematically by two dimensionless constants which characterize its magnitude and the region of influence. The physical model developed to account for precursory cooling consists of an infinitely extended vertical surface with the dry region ahead of the wet front characterized by an exponentially decaying heat flux and the wet region behind the moving film-front associated with a constant heat transfer coefficient. Apart from the two dimensionless constants describing the extent of precursory cooling, the physical problem is characterized by three dimensionless groups: the Peclet number or the dimensionless wetting velocity, the Biot number and a dimensionless temperature. Limiting solutions for large and small Peclet numbers have been obtained utilizing the Wiener-Hopf technique coupled with appropriate kernel substitutions. A semiempirical matching relation is then devised for the entire range of Peclet numbers. Existing experimental data with variable flow rates at atmospheric pressure are very closely correlated by the present model. Finally a comparison is drawn between the one-dimensional limit of the present analysis and the corresponding one-dimensional solution obtained by treating the dry region ahead of the wet front characterized by an exponentially decaying heat transfer coefficient.

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