---
product_id: 57124424
title: "Effect of Bulk Lubricant Concentration on the Excess Surface Density During R134a Pool Boiling with Extensive Measurement and Analysis Details"
brand: "nist"
price: "KD 7.77"
currency: KWD
in_stock: true
category: "Paperback"
url: https://www.desertcart.com.kw/products/57124424-effect-of-bulk-lubricant-concentration-on-the-excess-surface-density
store_origin: KW
region: Kuwait
---

# Effect of Bulk Lubricant Concentration on the Excess Surface Density During R134a Pool Boiling with Extensive Measurement and Analysis Details

**Brand:** nist
**Price:** KD 7.77
**Availability:** ✅ In Stock

## Quick Answers

- **What is this?** Effect of Bulk Lubricant Concentration on the Excess Surface Density During R134a Pool Boiling with Extensive Measurement and Analysis Details by nist
- **How much does it cost?** KD 7.77 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.com.kw](https://www.desertcart.com.kw/products/57124424-effect-of-bulk-lubricant-concentration-on-the-excess-surface-density)

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## Description

This paper investigates the effect that the bulk lubricant concentration has on the non-adiabatic lubricant excess surface density on a roughened, horizontal flat pool-boiling surface. Both pool boiling heat transfer data and lubricant excess surface density data are given for pure R134a and three different mixtures of R134a and a polyolester lubricant (POE). A spectrofluorometer was used to measure the lubricant excess density that was established by the boiling of a R134a/POE lubricant mixture on a test surface. The lubricant is preferentially drawn out of the bulk refrigerant/lubricant mixture by the boiling process and accumulates on the surface in excess of the bulk concentration. The excess lubricant resides in an approximately 40 mm layer onthe surface and influences the boiling performance. The lubricant excess surface density measurements were used to modify an existing dimensionless excess surface density parameter so that it is valid for different reduced pressures. The dimensionless parameter is a key component for a refrigerant/lubricant pool boiling model given in the literature. In support of improving the boiling model, both the excess measurements and heat transfer data are provided for pure R134a and three R134a/lubricant mixtures at 277.6 K. The heat transfer data shows that the lubricant excess layer causes an average enhancement of the heat flux of approximately 50 % for the 0.5 % lubricant mass fraction mixture relative to pure R134a heat fluxes between 4 kW/m2 and 20 kW/m2. Conversely, both the 1 % and the 2 % lubricant mass fraction mixtures experienced an average degradation of approximately 60 % in the heat flux relative to pure R134a heat fluxes between approximately 4 kW/m2 and 20 kW/m2. This study is an effort toward generating data that can be used to support a boiling model that can be used to predict whether lubricants degrade or improve boiling performance.

## Features

- Effect of Bulk Lubricant Concentration on the Excess Surface Density During R134a Pool Boiling with Extensive Measurement and Analysis Details

## Images

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*Product available on Desertcart Kuwait*
*Store origin: KW*
*Last updated: 2026-02-23*