1) The document discusses heat transfer via external forced convection, specifically over flat plates, cylinders, spheres, and tube banks. It provides equations and correlations for calculating the Nusselt number, heat transfer coefficient, friction factor, and drag coefficient in these situations.
2) Key aspects covered include the transition from laminar to turbulent flow, variations in the local heat transfer coefficient, and the effects of surface roughness.
3) Flow over tube banks is also analyzed, considering both inline and staggered tube arrangements. Correlations are given for calculating the average Nusselt number in these tube bank configurations.
It includes details about boundary layer and boundary layer separations like history,causes,results,applications,types,equations, etc.It also includes some real life example of boundary layer.
It includes details about boundary layer and boundary layer separations like history,causes,results,applications,types,equations, etc.It also includes some real life example of boundary layer.
This pdf includes about the submerged bodies and the forces acting on the submerged bodies. Different terminologies are discussed. Definitions of different bodies in the fluid are discussed as well.
It is small pdf with great knowledge, hope it will be helpful to the students.
fluid Motion in the presence of solid particlesUsman Shah
This slide will explain you the chemical engineering terms .Al about the basics of this slide are explain in it. The basics of fluid mechanics, heat transfer, chemical engineering thermodynamics, fluid motions, newtonian fluids, are explain in this process.
In this paper, an analysis was done on laminar boundary layer over a flat plate. The analysis was performed by changing the Reynolds number. The Reynolds number was changed by changing horizontal distance of the flat plate. Since other quantities were fixed, the Reynolds number increased with increment of horizontal distance. Iterations were increased in scaled residuals whenever the Reynolds number was increased. Maximum value of velocity contour decreased with the increment of the Reynolds number. The value of the largest region of velocity contour decreased with the increment of the value of the Reynolds number and it also affected the appearance of contour. The value of pressure contour increased with the increment of the Reynolds number. Vertical distance versus velocity graph was not depended on the Reynolds number. In this graph, the velocity increased rapidly with the increment of vertical distance for a certain period. After that, the velocity decreased slightly with the increment of vertical distance. Finally, the velocity became around 1.05 m/s.
Fluid Mechanics-Shear stress ,Shear stress distribution,Velocity profile,Flow Of Viscous Fluid Through The circular pipe ,Velocity profile for turbulent flow Boundary layer buildup in pipe,Velocity Distributions
This pdf includes about the submerged bodies and the forces acting on the submerged bodies. Different terminologies are discussed. Definitions of different bodies in the fluid are discussed as well.
It is small pdf with great knowledge, hope it will be helpful to the students.
fluid Motion in the presence of solid particlesUsman Shah
This slide will explain you the chemical engineering terms .Al about the basics of this slide are explain in it. The basics of fluid mechanics, heat transfer, chemical engineering thermodynamics, fluid motions, newtonian fluids, are explain in this process.
In this paper, an analysis was done on laminar boundary layer over a flat plate. The analysis was performed by changing the Reynolds number. The Reynolds number was changed by changing horizontal distance of the flat plate. Since other quantities were fixed, the Reynolds number increased with increment of horizontal distance. Iterations were increased in scaled residuals whenever the Reynolds number was increased. Maximum value of velocity contour decreased with the increment of the Reynolds number. The value of the largest region of velocity contour decreased with the increment of the value of the Reynolds number and it also affected the appearance of contour. The value of pressure contour increased with the increment of the Reynolds number. Vertical distance versus velocity graph was not depended on the Reynolds number. In this graph, the velocity increased rapidly with the increment of vertical distance for a certain period. After that, the velocity decreased slightly with the increment of vertical distance. Finally, the velocity became around 1.05 m/s.
Fluid Mechanics-Shear stress ,Shear stress distribution,Velocity profile,Flow Of Viscous Fluid Through The circular pipe ,Velocity profile for turbulent flow Boundary layer buildup in pipe,Velocity Distributions
Understand the physical mechanism of convection and its classification.
Visualize the development of velocity and thermal boundary layers during flow over surfaces.
Gain a working knowledge of the dimensionless Reynolds, Prandtl, and Nusselt numbers.
Distinguish between laminar and turbulent flows, and gain an understanding of the mechanisms of momentum and heat transfer in turbulent flow.
Derive the differential equations that govern convection on the basis of mass, momentum, and energy balances, and solve these equations for some simple cases such as laminar flow over a flat plate.
Non dimensionalize the convection equations and obtain the functional forms of friction and heat transfer coefficients.
Use analogies between momentum and heat transfer, and determine heat transfer coefficient from knowledge of friction coefficient.
Boundary layer concept
Characteristics of boundary layer along a thin flat plate,
Von Karman momentum integral equation,
Laminar and Turbulent Boundary layers
Separation of Boundary Layer,
Control of Boundary Layer,
flow around submerged objects-
Drag and Lift- Expression
Magnus effect.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Online aptitude test management system project report.pdfKamal Acharya
The purpose of on-line aptitude test system is to take online test in an efficient manner and no time wasting for checking the paper. The main objective of on-line aptitude test system is to efficiently evaluate the candidate thoroughly through a fully automated system that not only saves lot of time but also gives fast results. For students they give papers according to their convenience and time and there is no need of using extra thing like paper, pen etc. This can be used in educational institutions as well as in corporate world. Can be used anywhere any time as it is a web based application (user Location doesn’t matter). No restriction that examiner has to be present when the candidate takes the test.
Every time when lecturers/professors need to conduct examinations they have to sit down think about the questions and then create a whole new set of questions for each and every exam. In some cases the professor may want to give an open book online exam that is the student can take the exam any time anywhere, but the student might have to answer the questions in a limited time period. The professor may want to change the sequence of questions for every student. The problem that a student has is whenever a date for the exam is declared the student has to take it and there is no way he can take it at some other time. This project will create an interface for the examiner to create and store questions in a repository. It will also create an interface for the student to take examinations at his convenience and the questions and/or exams may be timed. Thereby creating an application which can be used by examiners and examinee’s simultaneously.
Examination System is very useful for Teachers/Professors. As in the teaching profession, you are responsible for writing question papers. In the conventional method, you write the question paper on paper, keep question papers separate from answers and all this information you have to keep in a locker to avoid unauthorized access. Using the Examination System you can create a question paper and everything will be written to a single exam file in encrypted format. You can set the General and Administrator password to avoid unauthorized access to your question paper. Every time you start the examination, the program shuffles all the questions and selects them randomly from the database, which reduces the chances of memorizing the questions.
2. • Aliran fluida dipermukaan benda solid sering terjadi
dalam praktek sebagai : gaya seret (DRAG) seperti
pada mobil, tiang listrik, pohon, pemipaan bawah laut,
kemudian gaya angkat (LIFT) seperti pada sayap
pesawat, gaya angkat keatas (upward draft) seperti
hembusan debu, pendinginan logam, uap air dll.
• Free-stream velocity 𝑼∞(kecepatan aliran bebas):
Kecepatan fluida aliran bebas yang biasanya jaraknya
cukup jauh dari sebuah permukaan solid, atau diluar
wilayah kecepatan lapisan batas.
• Upstream velocity V (approach velocity) kecepatan
aliran fluda pada saat mendekati benda (body) solid
dari jarak tertentu.
• Kecepatan fluida memiliki kisaran dari nol pada
permukaan solid (non-slip condition) sampai dengan
free-stream velocity (kecepatan aliran bebas) yang
cukup jauh dari permukaan solid tadi.
DRAG AND HEAT TRANSFER IN EXTERNAL FLOW
3. FRICTION AND PRESSURE DRAG
• Drag: Gaya yang diberikan aliran fluida yang
menerpa sebuah benda (body) dan parallel pada
arah aliran
• Komponen tekanan dan tegangan geser pada
dinding pada arah normal terhadap aliran
cenderung memindahkan body pada arah tersebut.
Jumlah keduanya dinamakan gaya lift (gaya angkat)
• Baik tegangan geser pada dinding dan tekanan
berkontribusi terhadap gaya drag dan gaya lift
(a) Drag force acting on a flat plate parallel to the flow depends
on wall shear only. (b) Drag force acting on a flat plate normal
to the flow depends on the pressure only and is independent
of the wall shear, which acts normal to the free-stream flow.
Skema untuk mengukur gaya tarik (drag) yang terjadi pada mobil di terowongan
udara (wind tunnel).
4. Gaya Drag FD bergantung pada rapat jenis fluida, upstream velocity
V, dan ukuran dan bentuk, orientasi posisi body/benda tersebut
terhadap aliran. Karakteristik drag suatu benda diberikan pada
angka tak berdimensi yakni koefisien drag (drag coefficient) CD yang
didefinisikan sebagai:
Koefisien drag terdiri dari skin friction drag ( friction drag)
akibat pengaruh tegangan geser pada dinding w yang
menyebabkan efek gesekan dan tekanan P atau
dinamakan pressure drag.
GAYA DRAG FD (DRAG FORCE)
5. • Pada angka Reynolds yang rendah, komponen
drag lebih banyak dipengaruhi friction drag.
• Friction drag proporsional terhadap luas
permukaan.
• Pressure drag proporsional dengan area frontal
dan beda tekanan pada bagian depan dan
belakang benda (body) yang terlingkupi oleh
aliran fluida.
• Pressure drag biasanya dominan untuk benda
tumpul (blunt body) and diabaikan pada benda
yang bentuknya ramping (streamlined bodies)
• Ketika aliran fluida berpisah dengan benda
(body), ia akan membentuk suatu wilayah aliran
yang terpisah (separated region) antara body
dan aliran bebas.
• Separated region: wilayah ber tekanan rendah
dibelakan benda (body) yang bersirkulasi
kembali dan terjadi putaran balik.
• Semakin besar separated region ini, semakin
besar pressure drag yang terjadi.
Wake: The region of flow trailing the body
where the effects of the body on velocity are
felt.
Viscous and rotational effects are the most
significant in the boundary layer, the
separated region, and the wake.
6. Angka Nusselt lokal dan rata-
rata:
Angka Nusselt rata-rata:
Temperatur film:
Koefisien gesek rata-rata:
Koefisien perpindahan kalor
rata-rata:
Laju perpindahan kalor:
KORELASI DENGAN HEAT TRANSFER
7. ALIRAN PARALLEL DIATAS PERMUKAAN PLAT DATAR
Transisi dari aliran laminar ke turbulent bergantung pada geometri permukaan, kekasaran permukaan, upstream
velocity, temperature permukaan dan jenis fluida, diantara semua ini, perubahannya dapat dikarakterisasi
sangat baik dengan Angka Reynolds. Angka Reynolds pada jarak x dari ujung depan plat datar dapat dihitung
dengan persamaan:
Nilai umum yang biasanya banyak digunakan
sebagai acuan Angka Reynolds kritis adalah
Nilai actual diatas untuk plat datar sangat
mungkin bervariasi dari 105 to 3 106, tergantung
kekasaran permukaan, level turbulence dan
variasi tekanan di sepanjang permukaan.
8. KOEFISIEN GESEK
Kombinasi aliran laminar + turbulent:
Koefisien gesek rata-rata disepanjang
permukaan didapatkan dengan mengintegralkan
koefisien gesek local sepanjang permukaan.
Nilai yang ditunjukkan disini adalah untuk
lapisan batas kecepatan laminar pada plat datar.
Tebal lapisan batas kecepatan dan koefisien gesek lokal
Koefisien gesek rata-rata disepanjang plat datar
10. Variasi koefisien perpindahan kalor dan gesekan
(local) pada aliran sepanjang plat datar
Angka Nusselt local pada lokasi x untuk aliran laminar yang mengalir pada plat datar didapatkan dengan
menyelesaikan persamaan diferensial energi menjadi dibawah berikut:
Terlihat pada gambar koefisien gesek
local dan koefisien perpindahan panas
pada turbulent lebih tinggi dibandingkan
pada aliran laminar.
Perhatikan, hx mencapai nilai maksimum
Ketika aliran menjadi turbulent (setelah
transisi) dan kemudian menurun dengan
factor sebesar x−0.2 pada arah aliran.
persamaan ini untuk permukaan plat
datar yang halus dan isothermal
KOEFISIEN PERPINDAHAN KALOR
11. Laminar +
turbulent
Koefisien perpindahan kalor rata-rata untuk plat datar dengan
kombinasi aliran laminar dan turbulent.
ANGKA NUSSELT UNTUK KOEFISIEN PERPINDAHAN KALOR RATA-RATA
For liquid metals
For all liquids, all Prandtl numbers
12. Churchill dan Ozoe (1973) mengusulkan persamaan dibawah untuk Angka Nusselt local yang dapat digunakan
untuk berbagai fluida, termasuk fluida metal cair dengan akurasi yang cukup baik
ANGKA NUSSELT UNTUK KOEFISIEN PERPINDAHAN KALOR RATA-RATA
UNTUK BERBAGAI FLUIDA*
15. ALIRAN PADA SILINDER MELINGKAR AND BOLA
Aliran pada silinder dan bola sering ditemui pada praktek engineering seperti pada aliran pipa penukar kalor
(heat exchanger). Pipa-pipa pada penukar kalor jenis shell and tube melibatkan aliran internal dan eksternal
disepanjang permukaan tabung/pipa.
Panjang karakteristik untuk geometri silinder dan bola diberikan oleh external diameter (D). Sehingga angka
Reynolds didefinisikan sebagai:
𝑅𝑒𝐷 =
𝑉 ∙ 𝐷
𝜈
=
𝜌 ⋅ 𝑉 ⋅ 𝐷
𝜇
Angka Reynolds kritis untuk aliran pada silinder melingkar (circular cylinder) atau bola (sphere) adalah sekitar
𝑅𝑒𝑐𝑟 ≅ 2 × 105. Sehingga lapisan batas tetap laminar jika 𝑅𝑒𝑐𝑟 ≤ 2 × 105 dan menjadi turbulent apabila 𝑅𝑒𝑐𝑟 ≥
2 × 105
.
Pada kecepatan yang sangat rendah, aliran fluida
menyelubungi silinder secara penuh. Aliran pada
wake region dikarakterisasi oleh formasi vortex
secara periodic dengan tekanan yang lebih rendah
dibandingkan titik stagnasi di bagian depan
silinder.
stagnation
point
vortex
wake
16. Pada aliran pada silinder atau bola, baik friction drag dan pressure drag dapat menjadi signifikan.
Analisa dimensional menunjukkan bahwa koefisien drag rata-rata CD for (silinder atau bola dengan
permukaan mulus) merupakan fungsi dari Angka Reynold, CD=f (ReD)
Gaya seret (drag force) pada angka Reynold yang rendah (Re<10) utamanya disebabkan oleh friction drag
sedangkan pada angka Reynold yang lebih tinggi (Re>5000) disebabkan oleh pressure drag
Kedua efek (friction dan pressure drag) signifikan pada angka Reynolds intermediate
Koefisien drag rata-rata untuk aliran cross flow pada silinder sirkular halus dan bola mulus.
Koefisien gesek menurun pada
kenaikan angka Reynold pada range
10 <Re<103. Penurunan koefisien
drag ini tidak mengindikasikan
menurunnya gaya seret (drag). Gaya
seret (drag force) proporsional
dengan kecepatan kuadrat sehingga
kenaikan kecepatan pada angka
Reynolds yang lebih tinggi biasanya
mengkompensasi penurunan
koefisien gesek.
17.
18. PENGARUH KEKASARAN PERMUKAAN
Kekasaran permukaan (surface roughness) pada umumnya meningkatkan koefisien drag dalam aliran
turbulen.
Ini terutama terjadi pada streamlined bodies
Pada circular cylinder atau bola (blunt bodies) kenaikan kekasaran permukaan dapat meningkatkan atau
menurunkan koefisien drag tergantung pada bilangan Reynolds.
Pengaruh kekasaran permukaan pada koefisien drag pada bentuk bola (sphere)
19.
20. • Aliran yang mengalir melintasi
silider dan bola, umumnya
terjadi pemisahan aliran flow
separation, yang sangat sulit
dianalisa.
• Aliran yang melintasi silinder
dan bola telah dipelajari secara
eksperimental oleh banyak
ilmuwan, dan beberapa korelasi
empiris telah dikembangkan
untuk koefisien perpindahan
kalornya.
Variation of the local heat transfer
coefficient along the circumference of a
circular cylinder in cross flow of air.
KOEFISIEN PERPINDAHAN KALOR
21. Properti fluida dievaluasi pada film temperature
Untuk aliran di permukaan cylinder
Untuk aliran dipermukaan bola (sphere)
Properti fluida dievaluasi pada free-stream temperature T, kecuali
s, dievaluasi pada Temperatur permukaanTs.
konstanta C dan m
diberikan pada tabel.
Persamaan diatas hanya untuk single silinder atau silinder yang
aliran melintasinya tidak terdapat pengaruh silinder (benda)
lainnya. Berlaku pada permukaan yang halus (smooth surfaces)
22.
23.
24. FLOW ACROSS TUBE BANKS
• Aliran melintang pada kumpulan tabung silinder banyak
ditemuai pada aplikasi perpindahan kalor seperti penukar
kalor (heat exchangers)
• Pada alat ini, sebuah aliran fluida (dapat air, refrigerant dllnya)
mengalir didalam tabung sedangkan fluida lainnya (air, udara
panas, refrigerant dll) bergerak dibagian luar pertabung pada
arah tegak lurus.
• Aliran yang mengalir didalam tabung dapat dianalisa sebagai
aliran pada tabung tunggal, dan mengalikan hasilnya dengan
jumlah tabung yang digunakan
• Untuk aliran diluar tabung, susunan tabung mempengaruhi
pola aliran turbulen pada level downstream, sehingga
bepengaruh pada perpindahan kalor yang terjadi.
• Susunan tabung yg umum in-line atau staggered
• Panjang characteristic adalah diameter luar tabung (D)
• Susunan tabung dikarakterisasi oleh transverse pitch ST,
longitudinal pitch SL , dan diagonal pitch SD diantara titik
pusat tabung.
upstream
downstream
25. diagonal
pitch
Susunan tabung
secara in-line dan
staggered pada tube
banks (A1, AT, dan
AD adalah area
luasan aliran pada
lokasi yang
diindikasikan dan L
adalah Panjang
tabung.
26. Semua property kecuali Prs
dievaluasi pada temperature
rata-rata arithmetic.
Persamaan (korelasi) angka Nusselt rata-rata yang diberikan pada Table 7–2 are adalah
untuk tube banks dengan baris (rows) lebih dari 16. Korelasi tersebut juga dapat
digunakan pada susunan tabung dengan NL < 16 akan tetapi perlu modifikasi
Persamaan diberikan padaTable 7-2
yang mana F adalah correction factor yang nilainya diberikan padaTable 7–3.
Untuk ReD > 1000, correction factor tidak bergantung (independent) dari angka Reynolds.
Log mean
temperature
difference
Exit temperature
Laju perpindahan kalor
NL < 16
29. DROP TEKANAN (PRESSURE DROP)
• f adalah faktor gesekan (friction
factor) dan c adalah faktor
koreksi (correction factor).
• Pemberian faktor koreksi
(correction factor) c is adalah
digunakan untuk menghitung
efek penyimpangan dari susunan
in-line (square arrangement) dan
staggered (equilateral
arrangement).